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(ESME) Journal of the 21st Annual Conference
Theme of the Year:
"Development of Railway Technology in Ethiopia"
May 7, 2017
The Journal is Published by the Ethiopian Society of Mechanical Engineering (ESME) P. O. Box: 17626, Addis Ababa, Ethiopia
Tel: +251 11 629 34 80
Fax: +251 11 629 25 16
E-mail: [email protected] www.esme-ethiopia.org
Copyright: Ethiopian Society of Mechanical Engineers (ESME), 2017
ESME Publication Council
All rights reserved. No part of this publication may be reproduced in a retrieval system or
transmitted in any form or by any means electronic, Mechanical, photocopying, recording,
or otherwise, without prior written permission from the Society.
The views expressed in the various articles in this publication are those of
the authors and do not necessarily reflect those of the author’s organization
or ESME.
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) (i)
Acknowledgement
I would like to thank all Executive Committee members, the Board, all those, without whose commitment
and support, this 21st Annual Conference would not have been possible.
Special thanks and gratitude are due to this year’s Sponsors and Advertisers whose generous support has
made the Conference possible.
HONORABLE SPONSOR ADDIS ABABA LIGHT RAIL TRANSIT SERVICE
SILVER SPONSORS
YASART ENGINEERING PLC
NATIONAL OIL ETHIOPIA PLC
METALS INDESTRY DEVELOPMENT INSTITUTE
MY WISH ENTERPRISE PLC
SINTEC ETHIOPIA PLC
THE FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA
MINISTRY OF SCIENCE AND TECHNOLOGY
NATIONAL CEMENT
INFINITY ENGINEERING PLC
BRONZE SPONSORS
BISELEX ETHIOPIA PLC
NATIONAL ALCOHOL & LIQUOR FACTORY
AMIO ENGINEERING PLC.
ETHIOPIAN INSURANCE CORPORATION
ACME ENGINEERING AND TRADING PLC
TIMEX TRADING PLC
FORTSCHRITT ELECTRO-MECHANICAL SERVICES PLC
Last but not least, my sincere thanks go to all of those who sacrificed their precious time to come and
participate in the Conference.
Thank you,
Alemayhu Negash
President
May, 2017
Ethiopian Society of Mechanical Engineers (ESME) (ii)
Journal of the 21st Annual Conference May, 2017
Table of Contents
ESME’s President Message
vii
Optimization of Green Sand Moulding by Taguchi Method Of
Parameter Design
Mohammed Awol
1 - 8
The Roles and Challenges of Mechanical Engineers in Consulting
Manufacturing Industries
Solomon Mulugeta Yigletu
10 - 23
Effects of Machine Arrangement on Performance of Sewing Lines of
Garment Production
Abebayehu Abdela
24 - 30
Design and Fabrication of Automatic Bottle Filling And Capping
Machine Using PLC
Kamilkerala, Dr. C.Jegadheesan
32 - 37
Design of Small scale Combine Harvester
Abdurhaman Teyib, Abubeker Temam, Yeshineh Jejaw
38 - 44
Ethiopian Society of Mechanical Engineers (ESME) (iii)
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) (iv)
Current Board and Council Members
Ato Alemayehu Negash
President
Ato Arefayne Tadesse
V. President and Engineering Council
Chairman
Ato Wubishet Getachew
Secretary
Ato Muaz Bediru
Controller and Education Training and Outreach
Council Chairman
Dr. Tesfaye Dama
Board Member
and Policy Council
Chairman
Ato Shewaferaw Girma
Board Member W/ro Samerawit
Abubeker
Board Member
Ato Derje Kassa
Board Member and
Institutional member
Representative
Ato Muktar Abdurahim
Board Member
Ato Solomon G/Egziabher
Auditor
Ato Yeheyis Assefa
Board Member and Publication Council
Chairman
Ato Feleke Dejene
Board Member and Members’ Affairs Council Chairman
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) (v)
Ethiopian Society of Mechanical Engineers (ESME) (vi)
Ethiopian Society of Mechanical Engineers (ESME) - vii-
Message of the President
Dear ESME Members and all stakeholders,
I would like first to convey my warmest greetings to you all.
On the occasion of the 21st ESME Annual Conference - Technical Session, it is a pleasure and an opportu-
nity to have the theme of the year ”Development of Railway Technology in Ethiopia”.
Within the framework of the Climate Resilient Green Economy transport strategy it was a prudent move by
the Council of Ministers to establish the Ethiopian Railway Corporation (ERC) with a mandate to develop
an integrated and high-capacity railway providing competitive and affordable passenger and freight trans-
port services. Ethiopia's bold vision for railway transport has begun to become a reality and this will reduce
overall transport costs, it will also initiate a change in the transport landscape from a road-based system to a
truly intermodal freight and passenger transport network.
Our national and eventually regional rail network needs to embrace a comprehensive path for technology
transfer, improve local technical skills as well as maintain skilled human resource to ensure sustainability.
As the national railway development plan is one best showcase of the art and science of mechanical engi-
neering it will provide professionals expertise in design and construction, signaling, communication, opera-
tion and maintenance.
I hope the deliberations in this particular ESME technical session will provide a valuable knowledge ex-
change platform to contribute to the beginning of railway industry and members and professionals will de-
velop successful networks. A comprehensive path for technology transfer to improve local technical skills
as well as maintain skilled human resources will be deliberated.
Ever grateful to our honorable sponsors who made it possible to organize this conference and with a heart-
felt thanks and appreciation to ESME staff who tirelessly worked to make it a success, I wish us all a fruit-
ful session and a bright new future abounding with lots of clean rail travel.
Alemayehu Negash
President
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) - viii-
The Ethiopian Society of Mechanical Engineers
(ESME)
The Ethiopian Society of Mechanical Engineers (ESME) was initiated at the founding conference held
on April 7 and 8, 1995 at Akaki Spare Parts and Hand Tools S. Co.
It is a non-governmental and non-profit, professional association. Its members are professional and
qualified mechanical engineers and other individuals who work in the areas of mechanical engi-
neering and allied professions.
ESME was registered on August 1995 with the Ministry of Justice and recently with the Charities and
Societies Agency (CSA) fulfilling the requirements thereof.
The total number of registered members as of August, 2015 is 1,283. It has also 43 active institutional
members.
Members of the Society enjoy a number of privileges among which are the following:
Participation in the different activities of the Society thereby expanding their professional hori-
zon;
Right to elect the Society‘s officers and be elected as an officer.
Have the opportunity to publish technical papers in the Society‘s bulletins and journals and/or
present the same at the Society‘s conferences, workshops, etc
Benefit from the Societies‘ activities such as: workshops, seminars, conferences, panel discus-
sions, technical trainings, study tours, periodic publications, etc.
Practice the profession by getting involved in the professional services delivered by ESME.
Be governed by the Codes of Ethics of the Society and get professional recognition by employ-
ers, certifiers, etc.
ESME‘s organizational structure includes a General Assembly, a Board of Directors, an Executive
Committee and a full time Secretariat. The General Assembly has full authority over the Society,
while the Board of Directors, elected every two years, is delegated by the General Assembly to over-
see the activities of the Society and decide on issues that do not require the intervention of the General
Assembly. Executive Committee members are also elected every two years and are responsible for the
management of the day to day activities of the Society, supported by a full time Secretariat, consisting
of an Executive manager & one support staff as well as the five Councils expected to actively partici-
pate in the execution of the Society‘s objectives.
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) (ix)
Journal of the 21st Annual Conference May, 2017
AMIO Multi Crop Thresher AMIO Maize Sheller AMIO Essential Oil Extractor AMIO Rope Washer Pump
AMIO Multi Crop Planter Industrial & Agricultural Machineries Manufacturing
Surface Pump
AMIO Engineering AMIO Treadle Pump
AMIO Plastic Molds
Submersible Pump
Oil Processing
Walking Tractor
Milk Processing
Combiner Harvester
Tel: - 0114 – 16 82 66,0114 – 16 50 03 Mob: - +251 911 22 26 41 +251 911 22 80 93 P.O.BOX: 25946
E-mail: [email protected] , [email protected] Addis Ababa, Ethiopia
Address :-Kera Gofa Mazoriya Filliya Building 3rd floor
Ethiopian Society of Mechanical Engineers (ESME) (x)
I. INTRODUCTION
Rail transport is of great importance to run the economic
system of every country. The inefficiency of rail trans-
port indirectly affects the efficiency and functioning of
the entire economic system of a country. The bogie of
railway vehicle is the primary structures, which support
the weight of car body and passengers, and under the
repeated external loading between rail and wheel.
Therefore, in order to have adequate strength and stiff-
ness against the external loading, bogie frames shall be
made of solid steel or welded structures based on quali-
tative metal materials. [1]
A bogie frame of railway vehicles plays an important
role in sustaining the static load from the dead weight of
a car body. Quasi-static loads occur periodically during
curving and braking operations, and cyclic dynamic
loads will be produced by an irregular rail surface and
relative movement of the attached equipment. Since
most of the structures of the bogie frame are welded,
hence, it is very susceptible to the fatigue failure under
such loads. To the best effect a fatigue durability analy-
sis of the bogie frame to ensure the required fatigue
strength of its welded structures is a relevant issue. [1]
1. FINITE ELEMENT MODELING
Finite element method modeling of the bogie frame
For the finite element analysis the researcher has se-
lected the motor bogie frame between the two kinds of
AALRT bogie frames. That is motor bogie frame and
trailer bogie frame. [3]
1.1 Fatigue Simulation Process using fatigue Simula-
tion program, FEMFAT
A simulation tool for fatigue assessment is FEMFAT,
developed by the Austrian company Magna Steyr. It is a
well-established software used by various companies in
the automotive and engineering industry. It carries out
fatigue assessment based on the results of finite element
analyses. The software consists of different modules.
Ethiopian Society of Mechanical Engineers (ESME) -1-
Fatigue durability Analysis for welded bogie
frame of AALRT By Ruhama Minwuyelet
Addis Ababa University, Addis Ababa Institute of Technology, School of Multidisciplinary Engineering,
Graduate Programin Railway Engineering Addis Ababa, Ethiopia, [email protected]
(Graduate Student in Mechanical Engineering (Rolling Stock) Program)
Abstract - This research paper forwards the fatigue durability analysis for the welded bogie frame of AALRT. The
purpose of the research is to observe the fatigue life of the welded bogie frame and to protect it from failure. In the
analysis of the research a three-dimensional finite element model of the bogie frame has been used to investigate the
effect of the applied loading force on the frame surface area and observing the effects at the welded joints. On the
bases of the model analysis the following results have been achieved. Output results without Sensitivity Factors: –
maximum and minimum log10 damage values are 30 and -7.09 respectively, maximum and minimum log10 endur-
ance safety factors are 1 and -5.11 respectively, maximum and minimum fatigue limits are 282 N/mm2 and 255 N/
mm2 respectively, and fatigue life is 2e^6. Output results with the small weld seam sensitivity Factor: – maximum
and minimum log10 damage values are 30 and -20 respectively, maximum and minimum log10 endurance safety
factors are 1 and -5.11 respectively, maximum and minimum fatigue limits are 282 N/mm2 and 0 N/mm2 respec-
tively, and fatigue life is 2e^6. Hence it is possible to conclude that the maximum damage result, which is 30 in
number is much exaggerated result, it is because the weld quality that the researcher has been taken is poor.
Whereas the fatigue limit at each analytical outputs has been proved to be the recommended value. The endurance
safety factor is below the anticipated value. Therefore a special attention should be given to the welded joints. Based
on sensitivity seam thickness results, it is possible to conclude that welded connections are almost nearer to failure
because they are highly exposed to residual stress. The study is significant and applicable as it introduces new
knowledge on fatigue life analysis of welded bogie frame in the minds of the beneficiaries of the study particularly to
those who are working in Railway Corporation.
Keywords: FEMFAT, Fatigue Life, Weld seam, Bogie Frame
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) -2 -
The FEMFAT MAX module is used for analyzing com-
ponents subjected to multi-axial loadings and it allows a
superposition of multiple stress states. All analysis
within this Thesis were carried out with FEMFAT MAX
version 5.0. In the following section the simulation
process for fatigue assessment of the bogie frame is out-
lined. FEMFAT WELD sensitivity analysis helps as-
sessing the influence of variation in weld geometry pa-
rameters on fatigue results. [2]
Weld parameters:-
Degree of weld penetration- η
Seam thickness-a
Seam inclination angle-α
Weld Gap
1.2 Joint Types for Sensitivity Analysis
There are different types of weld joints such as: - T-
Joint 45 0, T-Joint 90 0, Y-Joint, Butt Joint and Overlap
Joint. In her fatigue analysis of the bogie frame the re-
searcher has taken the welding type of T-Joint 90 0. The
welding type is demonstrated in the following table. [2]
TABLE 1
Weld Qualities for welding Parameters of T- Joint 90 0 [5]
Among the lables that justify different qualities of weld-
ing paramaters the researcher has choosen the poor
quality in order to get the output results at the worest
condition and to check the consquences of poor welding
performances.
FIGURES
1.1 Modeling using CATIA
Fig.1. - Modeling of the bogie frame and connecting by seam
welding using CATIA
1.2 Geometry of bogie frame using ANSYS work bench
for Exceptional loads
Fig.2. - Geometry of the bogie frame and applied forces on
the frame
Journal of the 21st Annual Conference May, 2017
Good
Quality
Standard
Quality
Poor
Quality
Weld Climb Angle α 1100 1000 900
Weld Thickness a 15 mm 10 mm 7 mm
Gap Dimension 0 mm 1.67 mm 5 mm
Degree of penetration
η
100% 50% 0%
Ethiopian Society of Mechanical Engineers (ESME) -3 -
1.3 ANSYS Results
Static analysis results for the bogie frame
Fig.3. - Static structure analysis deformation and Equivalent
(von - Mises) Stress results
1.4 FEMFAT WELD Pre-Processing
Fig.4 . - Input files in FEMFAT
1.5 FEMFAT WELD Post-Processing
RESULTS with FEMFAT WELD Module
Without Sensitivity Factor
Fig.5. - Local S-N curve Without Sensitivity Factor
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Ethiopian Society of Mechanical Engineers (ESME) -4 -
Journal of the 21st Annual Conference May, 2017
Fig. 7. - Damage value without any sensitivity factor
Fig.6 . - Fatigue Limit without any sensitivity factor
Ethiopian Society of Mechanical Engineers (ESME) - 5 -
Journal of the 21st Annual Conference May, 2017
Fig.10. - Fatigue limit at small seam thickness sensitivity
Fig. 11. - Damage value at small seam thickness sensitivity
Fig.8. -Endurance Safety Factor without any sensitivity factor
1.6 RESULTS with FEMFAT WELD Module sensitivity
seam thickness
Fig. 9. - Local S-N curve at small seam thickness
sensitivity
Ethiopian Society of Mechanical Engineers (ESME) - 6 -
Journal of the 21st Annual Conference May, 2017
III. DISCUSSION This paper focuses on assessing the bogie frame fatigue
life at its welded joints, by employing the sensitivity
effect of different weld geometry parameters.: - seam
thickness, inclination angle, penetration degree and
weld gap, but the presenter has selected weld seam
thickness parameter in her thesis because all weld pa-
rameters have similar output values. The output results
that have been obtained during the analysis of the re-
search shall be demonstrated in the following para-
graph.The maximum damage result which is 30 in num-
ber is much exaggerated; it is because the weld quality
that the researcher has taken is poor. Whereas the fa-
tigue limit at each analytical outputs has been proved to
be the recommended value which is 282 N/mm2. The
endurance safety factor has a maximum value of 1 and a
minimum value of -5.11. At the welded joint which is
the critical point of the frame has a value of safety fac-
tor -5.11 which is below the anticipated value. There-
fore the welded joints need better treatment. The maxi-
mum damage, fatigue limit and endurance safety factor
values are similar to that of the output results without
Sensitivity Factor, on the other hand the minimum dam-
age and fatigue limit are different, which means they
have got less value. This is because small seam thick-
ness minimizes the welding quality and its safety.
As it is mentioned earlier in the abstract attached the
purpose of this study is analyzing the fatigue durability
of the welded bogie frame of AALRT. In the current
simulation processes the FEMFAT software is used to
evaluate the fatigue life of the component. The multi-
axiality of the stress state needs to be taken into account
for the case of failure in order to obtain reliable results.
The researcher has conducted the analysis on welded
bogie frame model. From the post processing of FEM-
FAT different results have been found such as S-N
curve with endurance and cycle limits, fatigue limit,
damage and safety factor in different weld geometry
parameters . Those results show that seam welded joints
are highly sensitive area to failure and leads to a mini-
mum component`s fatigue life. Hence it is essential to
present different results as an output to predict accurate
seam weld life. The maximum damage result which is
30 in number is much exaggerated result comparing to
that of the reviewed research papers; it is because the
weld quality that the researcher has been taken is poor.
Whereas the fatigue limit at each analytical outputs has
been proved to be the recommended value. The endur-
ance safety factor has a maximum value of 1 and a
Fig.12. - Log 10 Endurance safety factor at small seam thick-
ness sensitivity
Ethiopian Society of Mechanical Engineers (ESME) - 7 -
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) -8 -
minimum value -5.11 at the welded joint, which is be-
low the anticipated value. Therefore a special attention
should be given to the welded joints. Based on sensitiv-
ity seam thickness results, it is possible to conclude that
welded connections are almost nearer to failure because
they are highly exposed to residual stress.
ACKNOWLEDGEMENT
The author would like to acknowledge her advisor Dr.
Daniel Tilahun for his unreserved assistance and re-
source- full advice that encouraged the researcher to
conduct the research successfully and courageously and
his kind support and guidance to publish her work. Also,
the author would like to take this opportunity to thank
ESME for encouraging and providing this opportunity to
publish her own work.
REFERENCE
1. K.W. Jeona, K.B. Shinb* and J.S. Kimc,a ; A study
on fatigue life and strength of a FRP composite bo-
gie frame for urban subway trains.
Daejeon, Korea, Load Test Method of Vehicle Body
and Bogie Frame for Korean Maglev Vehicle the
21st International Conference on Magnetically Levi-
tated Systems and Linear Drives, October 10-13,
2011, Daejeon, Korea.
2. HARTWIG PÖRTNER Multi-axial Fatigue Models
for Composite Lightweight StructuresMaster‘s Thesis
in Applied Mechanics Chalmers University of Tech-
nologyGöteborg, Sweden 2013.
―Fatigue Assessment with FEMFAT WELD Including
Sensitivity Analysis‖ 5th FEMFAT User meeting
USA, Nov 8th 2012 2
3. Technical specifications of LRT project documents for
Addis Ababa Ethiopia; China Railway Group
(CRECG) Project Manager Office for Light Rail Pro-
ject of Ethiopia July 2013.
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Ethiopian Society of Mechanical Engineers (ESME) -10 -
1. INTRODUCTION
Maintenance with multi-directional activities, resources,
measurement and management has been important to
rail transport operation organizations. Maintenance ex-
ists because we have physical assets which deteriorate
[1]. However, in recent years the need to manage the
multiple factor of maintenance more effectively has
gained important attention due to changing operational
technologies and the changing organizational role of
maintenance. In the case of light rail transport organiza-
tion, maintenance has a broader perspective. In such
organizations, the scope of maintenance has shifted
from a narrowly-defined operational perspective to an
organizational strategic perspective. The main chal-
lenges faced by organizations today are choosing the
most efficient and effective strategies to enhance and
continually improve operational capabilities, reduce
maintenance costs and to achieve competitiveness in the
industry [2]. Implementation of efficient maintenance
system early on the initial establishment of a business
organization has good opportunity if it is carefully stud-
ied and designed with overall objective of an organiza-
tion.
[3] Showed that most Swedish firms, i.e. about 81%, use
the accumulated knowledge and experience within the
company as a method for maintenance selection. Be-
sides, about 31% use a method based on modeling the
time to failure and optimization. About 10% use failure
mode effect and criticality analysis (FMECA) and deci-
sion trees and only 2% use multiple criterion decision
making (MCDM). On problem investigation phase of
this research, it is observed that most of Ethiopian or-
ganizations also use their own experience or the overall
government policies as their maintenance strategy.
Therefore, there should be a need to develop effective
maintenance strategy, which can achieve the overall
goals of the maintenance activity in a cost effective way.
This research tries to use one of MCDM approaches,
AHP as a method for selection of maintenance strategy.
2. REVIEW OF MAINTENANCE FACTORS,
STRATEGY AND AHP ALGORITHM
2.1 Maintenance factors
Usually maintenance strategy consists of various critical
success factors that are necessary to achieve the overall
Selection of Maintenance Strategy by AHP Algorithm for
Light Rail Transit System MulukenAssefa1, Daniel Tilahun2
1 Schoolof Industrial and Mechanical Engineering, Addis Ababa University Institute of Technology (AAIT),
Addis Ababa, Ethiopia,[email protected]
2 School of Industrial and Mechanical Engineering, Addis Ababa University Institute of Technology (AAIT).
Addis Ababa, Ethiopia
Abstract-The main objective of this research is identifying key maintenance factors and modeling maintenance
strategy by Analytic Hierarchy Process to select the possible priorities of maintenance strategy by using ex-
pert decision software. Selection of efficient maintenance strategy can be achieved by pair wise comparison of
identified functions. This qualitative survey assessed the opinion of 14 maintenance engineers and technicians,
among them 7 experts work in METEC locomotive assembly division. The research method comprises identi-
fication of maintenance factors and selection of possible maintenance strategies for Light Rail Transit system.
The analysis shows that Safety (38.2%) becomes the most critical factor on selection of maintenance strategy.
Value adding activities (20%), implementation cost (13.2%), support system integration (11.5%), implementa-
tion capability (8.2%), stock & material management (5%) and performance measurement (3.9%) are the
successive priority factors on implementation of maintenance strategy. The five strategies, Corrective Mainte-
nance, Preventive Maintenance, Condition Based Maintenance, Reliability Center Maintenance and Total
Productive Maintenance are identified as a possible maintenance strategies. The analysis discovered that Total
productive maintenance is the most suitable strategy to be implemented for Light Rail Transit system and
Corrective maintenance is the least to follow. Finally sensitivity and sanity is checked for the analysis.
Keywords - Maintenance Strategy, Light Rail Transit (LRT), Analytic Hierarchy Process (AHP), Maintenance factors
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) -11 -
goals for maintenance. There should be methods for es-
tablishing the relationship between the operational reli-
ability, the condition of the railway vehicle, track related
infrastructure, maintenance work carried out and meas-
uring the performance of maintenance strategy. Identifi-
cation of maintenance key criteria is the most important
stage in the formulation of AHP model. To achieve this
task the research tried to identify 42 key maintenance
factors and 25 factors selected through first level ques-
tioner by factor analysis. The selected factors grouped as
7 maintenance factors. These are safety, implementation
cost, added value, implementation capability, perform-
ance benchmarking, stock and material management and
support system integration.
I. Safety
According to [4] the safety management system must
include systems and procedures for the review of the
management system at specified periods. Safety poli-
cies, procedures and guidelines maintains healthy work-
ing environment. Interruptions in operations due to fail-
ure may form a source of hazard to passengers, train
operators, workers and the nearby system. The mainte-
nance management system should be fully integrated
with safety management system; therefore this research
outlined passenger safety, worker safety & system
safety as main factors to implement efficient and effec-
tive maintenance strategy. The higher the strategy en-
sures safety the higher the rank.
II. Implementation Cost
Maintenance cost usually consists of Direct costs; man-
power, spare parts, tools, transportation, training and
methods. There are also Indirect costs which are all the
costs that may arise due to planned and unplanned main-
tenance actions, e.g., lost operations costs, accidents.
Those are not the only costs in maintenance organiza-
tion. Approaching specific maintenance strategy will
cost significant amount of investment. This research
categorizes maintenance strategy implementation cost as
hardware cost, software cost, operation and maintenance
cost of the system and training & development of per-
sonnel to use special tools and methods to perform the
maintenance activities. The lower implementation cost
of the strategy the higher the rank.
III. Value Added
The customer requirement of light rail transit system is
realizing dependable passenger transport. Their satisfac-
tion is measured by factors like reliability, availability
and quality of service. In addition to providing mass
transit transport for the population the ultimate goal of
transport operation like light rail transit is gaining rea-
sonable profit in order to cover the high cost of train and
infrastructure operation and maintenance management.
Proven quality combined with value adding mainte-
nance strategy concepts makes the operator meet the
highest standards in terms profit oriented business strat-
egy. The higher the strategy ensures value adding fac-
tors the higher the rank.
IV. Implementation Capability
Once the maintenance strategy is selected the detail fea-
sibility study should be checked. One factor of feasibil-
ity study is the firms‘ implementation capability. The
first indicator will be financial capability to invest on
selected strategy. For example strategies like CBM need
high investment on initial cost their financial profit will
be known at overall life cycle profit. The availability of
technology with personal capability combined with hu-
man and managerial willingness to implement is the
main factors of efficient maintenance strategy. The
higher the organization has implementation capability
the higher the rank.
V. Maintenance Performance measure
Maintenance performance measurement enables a solid
basis for establishing where maintenance related im-
provements are most appropriate at any given time [5].
Performance measures can be classified in a number of
ways. Maintenance Performance measurement system
can be used for strategic and day-to-day operations of
the organization, control implementations of improve-
ments and monitoring of the cost centers. The research
categorizes the maintenance performance factors based
on [6] finding. The maintenance performance indicators
are equipment performance measure, maintenance cost
performance measure and maintenance process meas-
ures. The higher the strategy measures the performance
the higher the rank.
VI. Stock & Material Management
If there is maintenance there is also repair and replace-
ment of parts. The parts and consumables are either pur-
chased with the train or to be purchased when the dam-
age occur that is depending on the firm‘s maintenance
philosophy. Stock keeping and material management
have significant contribution to the firm‘s business proc-
ess but it needs high investment and man power. To
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) -12 -
have optimized spare part, material procurement and
stock keeping should be integrated with in maintenance
strategy formulation. Part availability, purchase plan-
ning and inventory control considered as stock and ma-
terial management factors the higher the strategy suit-
able for material management the higher the rank.
VII. Support System Integration
In light rail transit maintenance and repair organization
the main function next to transport operation is mainte-
nance department but that doesn‘t mean that it is the
only department in the organization. There are supports
functions like finance, procurement and material man-
agement, human resource management, marketing,
sales, Information technology, research & development
and engineering & technical support. If the competence
of the strategy to integrate the maintenance support de-
partment such as operation, procurement & material
management, Engineering and technical support & IT is
high the selection rank become high.
2.2. Maintenance strategy
Maintenance strategy is a Management method used in
order to achieve the maintenance objectives. [7] Mainte-
nance Objectives are the targets assigned to or accepted
by the management and organization. The content in the
maintenance strategy is a mix of techniques and/or poli-
cies which depends on factors such as the nature of the
plant, maintenance goals or equipment that will be
maintained, work environment and work flow pat-
terns [2].A number of maintenance strategies and con-
cepts have been suggested by intellectuals or imple-
mented by an organization internationally. Five of the
maintenance strategies selected for this research and
LRT operator experiences. The candidate strategies ex-
plained as follows:-
Corrective Maintenance is also referred as, failure
based maintenance, breakdown maintenance or run to
failure strategy[8]. It is the original maintenance strat-
egy appeared in industry [9]. In this strategy an item is
allowed to fail before maintenance is executed. This
strategy is appropriate when the consequence of failure
is small. It can be used where the failure of equip-
ment do not have a greater impact on availability or
service for productive use of an organization.
Condition Based Maintenance is a planned maintenance
approach where failure or break down of rolling stock
and infrastructure is avoided by using pre- diagnostics
tools.. Basically, this approach tries to forecast or
predict the wear and tear or life of equipment by
using different methods and accordingly recommends a
corrective action. This form of maintenance strategy as
defined by [10] maintenance is performed with the as-
sistance of diagnostic tools, on a timely schedule; daily,
weekly, or monthly. The diagnostics equipment meas-
ures physical conditions such as temperature, vibration,
noise, corrosion, and other revealing signs, which may
lead to premature equipment failure [10]. This kind of
strategy needs high technology, sophisticated sensors
and diagnosis tools.
Preventive Maintenance strategy described by [11], It is
a maintenance strategy that reduces the frequency and
random failure by performing planned repairs, replace-
ment, overhauling, lubricating, cleaning and inspecting
at specific time intervals. The intent of the PM strategy
is to minimize the probability of equipment failure pre-
maturely by conducting maintenance before the failure
of the equipment. In this strategy replacement or repair
at a fixed time after the installation of facility is carried
out which is generally independent of its condition.
The time period used to construct a maintenance sched-
ule can be either calendar time or component running
time.
Reliability Centered Maintenance (RCM) is a methodol-
ogy that determines what must be done to ensure that
the asset continues fulfilling its intended functions in its
present operating context [12]. The success of this ap-
proach depends on the availability of failure data, analy-
sis methods and operating experience to achieve its tar-
get. RCM has implementation difficulties due to un-
availability of plant failure data. This maintenance strat-
egy focuses on optimizing preventative and predictive
maintenance, which results in an increase in equipment
effectiveness while minimizing maintenance cost.
Total Productive Maintenance (TPM) the prime objec-
tive of TPM is to maximize equipment effectiveness
and productivity and eliminate all machine losses cre-
ate a sense of ownership in equipment operators through
a program of training and involvement promote continu-
ous improvement through small group activities involv-
ing production, engineering, and maintenance person-
nel[13]. Each enterprise has its own unique definition
and vision for TPM [14]. But in most cases there are
common elements and themes. These are Asset strategy,
Empowerment, Resources Planning, scheduling, Meas-
urement, continuous improvement team, Processes, Sys-
tems and Procedures. This maintenance philosophy re-
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) -13 -
quires active participation by all employees in the or-
ganization, including management. This kind of mainte-
nance focuses on increasing the overall equipment effec-
tiveness (OEE). According to [3] OEE is an excellent
indicator of how well TPM is implemented in organiza-
tion.
2.3. AHP Algorithm
The analytic hierarchy process (AHP) methodology,
which was developed by [15], it is a one of MCDM
method and it is powerful tool in solving complex deci-
sion problems. The AHP helps the researchers organize
the critical aspects of a problem into a hierarchical struc-
ture similar to a family tree. By reducing complex deci-
sions to a series of simple comparisons and rankings,
then synthesizing the results, the AHP not only helps the
researchers arrive at the best decision, but also provides
a clear justification for the choices made [16].In the
AHP approach, the decision problem is structured hier-
archically at different levels with each level consisting
of a finite number of decision elements. The upper level
of the hierarchy represents the overall goal, while the
lower level consists of all possible alternatives; one or
more intermediate level embodies the decision criteria
and sub-criteria [17].
In this research AHP is considered as an ideal system-
atic approach for several reasons. First, the AHP consid-
ers both qualitative and quantitative aspects of research
and combines them into a single empirical inquiry [18].
The AHP is able to adopt a qualitative way in building
the decision hierarchy and also uses a quantitative ap-
proach in data collection and analysis to test the attrib-
utes of the models by using a self-completed question-
naire. The AHP has the capability to combine various
types of criteria in a multi-level decision structure to
obtain a single score for each alternative to rank the al-
ternatives among the available multi attribute ap-
proaches [19]. Second, the selection of AHP as a
method of analysis in this study is also determined by
the size of the sample population.
The AHP is an analytical method which permits a small
survey group [20]. It is thus helpful in collecting and
analyzing data from a small group of experts who have
real experience in maintenance management. This ex-
plains why the AHP is appropriate for use as a method
of test. Furthermore, the AHP provides a function of
seeking an expert‘s judgments and provides a consis-
tency check which makes it a reliable way to determine
the priorities of a set of factors, which may then be in-
corporated into other evaluation systems [18]and
[21].By using the AHP approach, different levels of
contribution of the selection factors, criteria and sub
criteria towards selection of maintenance strategy are
identified.
3. RESEARCH METHODOLOGY
The overall research mainly includes five tasks. The
main research process is illustrated as follows.
I. Literature review: - The first step of the research is
gathering the maintenance critical factors from dif-
ferent literature and the researcher previous experi-
ence. Then forty two maintenance factors are col-
lected.
II. Factor analysis: - The collected maintenance critical
factors are not equally important for the selection of
maintenance strategy. Therefore the identified factors
refined based on factor analysis with likert scale. For
this survey twelve rolling stock technicians and engi-
neers are participated. As a result 25 critical factors
are selected as main indicators for the selection of the
strategy. Then the 25 sub-criteria further regrouped
by 7 main critical factors.
III. Modeling of maintenance strategy: - AHP Algorithm
is used to structure the decision problem into a hier-
archical model. This involves the decomposition of
the decision problem into elements according to their
common characteristics. In this study, the hierarchies
illustrate the attribute for selecting efficient mainte-
nance strategy selection for LRT system. The top
level is the selection goal (i.e. prioritization of critical
selection criteria for efficient maintenance strategy
selection), and following this are the selection factors
(main criteria) and selection sub-criteria the third
level) and finally the alternative maintenance strat-
egy. Using criteria, sub-criteria and alternatives, a
hierarchical model is constructed to apply AHP algo-
rithms. Then relationship among criteria and sub-
criteria are determined and reflected in the hierarchi-
cal model. Fig.1 below shows the hierarchical struc-
ture of the maintenance strategy selection model,
which includes four levels. The top level of the hier-
archy represents the strategic goal of the model,
while the second level of the hierarchy consists of
seven main maintenance strategy selection criteria,
the third level of the hierarchy contains twenty two
sub criteria to fulfill the strategic goal and the last
hierarchy shows the possible alternative strategies.
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) -14 -
Fig.1. - AHP model for selection of maintenance strategy
IV. Analysis and data collection
After formation of relationship modeling by AHP
algorithm the next step is the collection of data by
using AHP questioner the combined rating of all
experts‘ opinion on selection of maintenance strat-
egy transferred in expert decision software and ana-
lyzed. Each set of pair wise comparisons was
checked for consistency and revised if necessary
until the maximum inconsistency was below ten per-
cent, which is considered the minimum standard
level [15]. The results were synthesized throughout
the model to yield the overall priorities of the strate-
gic alternatives.
V. Result and discussion
Quantitative data obtained from qualitative expert
judgment by using super decision software.
4. RESULT AND DISCUSSION
4.1 Result
After collection of data by using AHP questioner the
combined rating of all experts‘ opinion transferred in
expert decision software and analyzed. Each set of pair
wise comparisons was checked for consistency and
revised if necessary until the maximum inconsistency
was below ten percent, which is considered the mini-
mum standard level [15]. The results were synthesized
throughout the model to yield the overall priorities of
the strategic alternatives. The result is demonstrated on
fig.2TPM is the most suitable maintenance strategy to
be implemented on light rail transit system. CM is the
list preferable maintenance strategy to be implemented
in light rail transit.
Fig.2. - The priority of alternative maintenance strategy.
According to the analysis 35.1% priority is given to
TPM strategy due to its involvement of the overall em-
ployee participation on maintenance. Moreover it is a
strategy which insures OEE through continuous im-
provement. Learning and team building are the core task
of this strategy. The strategy doesn‘t need expensive
initial investment rather most of the investment is in
work process and employees way of thinking. The least
selected strategy is CM 9.26%; CM lacks most of the
modern maintenance strategy.
Fig.3. - Priority of maintenance factors (main criteria)
Based on the result of the analysis the experts give a
higher value for safety 38% and the lowest value is per-
formance measurement 3.8%. Value adding activities
become the second perferable criteria 20% . Implemen-
tation cost 13.2% ,the power of the strategy to integrate
with the different system 11.5%, an organization imple-
mentation capablity 8.2%, the effectiveness in stock
&material management 5% have a significant impact
on selection of maintenance strategy.
Journal of the 21st Annual Conference May, 2017
Fig.8. - Performance measurement sub-criteria‘s priority
Fig.9.- Stock and material control sub- criteria‘s priority
Fig.10. - Support system integration sub-criteria‘s priority
4.2. Sensitivity analysis
Sensitivity analysis was carried out by varying the
weights of the criteria and sub-criteria to determine the
stability of the decision reached by using the decision
model proposed in this study. Sensitivity is performed
Fig.4. - Safety sub-criteria‘s priority
Fig.5. - Value added sub-criteria priority
Fig.6. - Implementation sub-criteria priority
Fig.7. - Implementation capability criteria priority
Ethiopian Society of Mechanical Engineers (ESME) - 15 -
Journal of the 21st Annual Conference May, 2017
Fig.12. - Sensitivity graph with implementation cost priority
set to 0.70
The same procedure as the previous by changing the
priority of the performance measurement indicated by
the vertical line, is set to its original priority of 0.50 in
fig 13 priorities of the alternatives are then read from
the y-axis at the points where the vertical line crosses
the alternatives‘ lines. In fig 14 the priority of the per-
formance benchmarking indicated by the vertical line is
set to 0.9 the rank and values of alternative changed and
shown on table 2.
Fig13. - Sensitivity graph with performance benchmarking
priority set to 0.50
Fig.14. - Sensitivity graph with performance benchmarking
priority set to 0.902
by selecting a criterion (or sub-criterion) and changing
its priority, redistributing the change among the other
criteria (sub-criteria), and recalculating the priorities of
the alternatives to observe if any change occurred in
their ranking. A graphical representation of sensitivity
for the implementation cost criterion is shown in Fig
11and Fig 12 .Criterion priorities are read from the x-
axis; the alternatives‘ priorities are read from the y-axis.
In fig 11 the priority of the implementation cost indi-
cated by the vertical line, is set to its original priority of
0.50. Sensitivity is performed by varying the priority of
the implementation cost criterion by moving the vertical
line and determining the corresponding alternative pri-
orities. In Figure 12, it has been moved to the right to a
priority of about 0.70 and the order of the alternatives
has changed and shown on table 1.
Fig.11.Sensitivity graph with implementation cost priority set to 0.50
TABLE I
ALTERNATIVE RANKING WITH IMPLEMENTATION
COST PRIORITY CHANGE FROM 0.5 TO 0.7
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Journal of the 21st Annual Conference May, 2017
Alternative strategy
Sensitiv-
ity=0.5 Sensitivity=0.7 Rank
0.5 Rank
at
0.7 RCM 0.180 0.155 3 3
TPM 0.261 0.214 1 2
CBM 0.150 0.115 5 5
CM 0.251 0.333 2 1
PM 0.165 0.183 4 4
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) - 17 -
TABLE II
ALTERNATIVE RANKING WITH PERFORMANCE
BENCHMARKING PRIORITY CHANGE FROM 0.7 TO
0.902
Performing sensitivity on the criteria of safety, imple-
mentation capability, value added, part & material con-
trol and support system integration do not affect the first
ranked alternative, but in some cases RCM and CBM
switched. Similarly, sensitivity analyses of the sub-
criteria was also conducted and showed that the priori-
ties of the first alternative will not change.
5. CONCLUSION
In this paper maintenance strategy selection procedure
for LRT system is illustrated by AHP algorithm. Super
decision software is used for analysis. .Five alternative
maintenance strategies are considered seven main deci-
sion criteria and twenty-five sub criteria have been de-
termined. The criteria and alternatives structured by
AHP algorithm. The expert decision software estimates
the weights (priorities) of decision criteria using pair
wise comparison method. The result indicated that
safety is number one priority from maintenance strategic
factors followed by value adding factors. In addition, the
survey indicated that Total Productive Maintenance is
the most suitable strategy to be implemented for LRT
system and corrective maintenance is the least one.
REFERENCES
[1.] Moubray(1991), Reliability Centered Maintenance,
Butterworth Heinemann, Oxford, UK.
[2.] Terry wireman (2005), Industrial Press, Inc., Devel-
oping Performance Indicators for Managing Mainte-
nance, New York.
[3.] ImadAlsyouf, växjö (2004), Cost effective Mainte-
nance for Competitive Advantages University Press,
Sweden.
[4.] National Rail Safety Guideline (2008), National
Transport Commission, Australia.
[5.] Adyta Parida and UdayKumar(2009), Mainte-
nance Productivity and Performance Measure-
ment.
[6.] Albert H.C. Tsang (2000), Maintenance Perform-
ance Management in Capital Intensive Organiza-
tions, University of Toronto.
[7.] Alsyouf, I. (2007),The Role of Maintenance in
Improving Companies Productivity and Profitabil-
ity. International Journal of Production Econom-
ics.
[8.] A.D. Telang and AMIT Telang (2010), Compre-
hensive Maintenance Management.
[9.] Waeyenbergh, G. and Pintelon, L. (2002), A
Framework for Maintenance Concept Develop-
ment. International Journal of Production Eco-
nomics.
[10.] Sharma, R. K., Kumar, D., and Kumar, P. (2005),
FLM to Select Suitable Maintenance Strategies in
Process Industries Using ISO Model. Journal of
Quality in Maintenance.
[11.] Kamran Moghaddam, Tehran (2003), Preventive
Maintenance and Replacement Scheduling Mod-
els and Algorithms.
[12.] John Moubray (2000),The Case Against Stream-
lined RCM.
[13.] Nakajima, S (1988), Introduction to TPM, Pro-
ductivity Press, Cambrige, MA.
[14.] John D. Campbell (1995), Outsourcing in Mainte-
nance Management. Vol. 1 Issue 3. MCB UP Ltd.
[15.] Saaty, T.L. (1980), Analytic Hierarchy Process:
Planning, Priority Setting, Resource Allocation.
New York: McGraw-Hill.
[16.] Chin et al.,Chin K.S.,S. Chiu,V.M.R. Tummala
(1999), An Evaluation of Success Factors Using
AHP to Implement ISO 14001 based EMS,
[17.] Fariborz Y Patrovi (1994), Determining What to
Benchmark,Vol. 14 Issue: 6. MCB UP Ltd.
[18.] Eddie W.L. Cheng, Heng Li, (2001), Analytical
Hierarchy Process, Vol. 5 Issue 3. MCB UP Ltd.
[19.] Yudakul (2004), Selection of Computer-Integrated
Manufacturing Technologies using a Combined
Analytic Hierarchy Process and Goal Program-
ming Model. Robotic and Computer-Integrated
Manufacturing.
[20.] Eddie W.L. Cheng, Heng Li, Danny C.K. Ho.
(2002), Analytical Hierarchy Process (AHP), Vol.
6 Issue 4. MCB UP Ltd.
[21.] Ling Wanga, Jian Chua, Jun Wub (2007), Selec-
tion of Optimum Maintenance Strategies Based on
a Fuzzy Analytic Hierarchy Process. International
Journal of Production Economics, 2007.
Alterna-
tive strat-
egy
Sensitiv-
ity=0.5 Sensitiv-
ity=0.9 Ran
k 0.5 Rank
at 0.9
RCM 0.283 0.331 2 1
TPM 0.332 0.315 1 2
CBM 0.208 0.200 3 3
CM 0.068 0.048 5 5
PM 0.110 0.180 4 4
Ethiopian Society of Mechanical Engineers (ESME) - 18 -
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) - 19 -
Identification of the Best Material Combination between Wheel and Rail of Railway Vehicle with Minimum Wear Rate
Natnael Tesfamichael1, Habtamu Tkubet2
1 School of Industrial and Mechanical Engineering, Addis Ababa University Institute of Technology (AAIT),
Addis Ababa, Ethiopia, P.O. Box 31715, [email protected] 2 School of Industrial and Mechanical Engineering, Addis Ababa University Institute of Technology (AAIT).
Addis Ababa, Ethiopia, [email protected]
Abstract — Wear is a natural phenomenon that exists when two bodies, which are in contact, perform a relative mo-
tion; this is also true for the wheel and rail of a railway vehicle. This wear is mainly dependent on the type of mate-
rial they are made of. There is a tolerable level of wear that is safe to the railway operation. Once this critical wear
level is reached, it is mandatory to re-profile the wheel, grind the rail. However, after some time it will be worn out to
the level it can no more be used and the whole system must be replaced with a new one. This indicates that there is a
need to focus on the wear properties of wheel and rail materials in order to secure a safe and sustainable railway op-
eration.
This research tries to set new combinations (pairs) of wheel and rail materials, simulate them for wear performance
using a multi body simulation software (SIMPACK). An important criteria for the comparison is the hardness and
strength of the wheel/rail materials. Then compare the wear rate of the different combination and identify for the
best material combination with the minimum wear rate. Based on the simulation it is found that a softer wheel mate-
rial rolling on a relatively harder rail material has a minimum wear rate. But increasing the hardness of both wheel
and rails will not secure better wear performance. Safety is also considered in this research using the derailment coef-
ficient parameter. Based on the minimum derailment coefficient value among the combinations those with better
wear performance showed a better safety.
Key words - Wheel/ rail materials, hardness, material combination, wear rate.
1. INTRODUCTION Wear is a natural phenomenon that exists when two bodies,
which are in contact, perform a relative motion; this is also
true for the wheel and rail of a railway vehicle. This wear is
mainly dependent on the type of material they are made of.
There is a tolerable level of wear that is safe to the railway
operation. Once this critical wear level is reached, it is man-
datory to re-profile the wheel, grind the rail. However, after
some time it will be worn out to the level it can no more be
used and the whole system must be replaced with a new
one.
All the above process demands a lot of time, human effort
and costs large amount of money, so a small improvement
on the wear rate reduction could have a great impact on
such a large scale railway operation. There have been re-
searches made to reduce the wear rate. One of the most ef-
fective approaches is to play on the material, as mentioned
above the material in which the wheel is made of is differ-
ent from the one in which the rail is made.
There are different lists of materials for the rail and for the
wheel, which have been discovered by different research-
ers. All these materials are steel
based but with different hardness and other mechanical
properties. We can select or set new combination of mate-
rials like ER7 for the wheel and 60E1 for the rail. These
materials are recently used in Europe [4]. The word
‗combination‘, used in the above sentence is to indicate
that a matching between a wheel made of ER7 steel and a
rail made of 60E1steel material could be done for railway
operation. The aim of this research is to set new combina-
tions (pairs) of wheel and rail materials, test them for wear
performance then compare the result with the existing
ones and identify for the best material combination.
Journal of the 21st Annual Conference May, 2017
4.1.1 Major Technical Parameters based on Addis Ababa LRT specifications [24]
Tramcar Width: 2650mm Tramcar Height: 3700mm Track Gauge: 1435 mm Minimal Curve Radius: 50m for mainline and
30m for parking garage Minimal Vertical Curve Radius: 1000m Tramcar Length: 28400 mm Wheel Base: 1900 mm for power bogie and
1600 mm for driven bogie Wheel radius = 600mm Axle load = 25ton Maximum operation speed = 70 km/hr
Fig.2. - Contact positions of the wheel-rail pair
Stiffness and Damping
- The stiffness and damping values used are: cx =
cy= 10 kN/mm (107N/m), cz= 5kN/mm (5*105N/
m), and dx = dy= dz= 20 kNs/m (2* 105Ns/m).
- Create a Force Element of type 5
Vertical Load
The same Force Element also exerts the vertical
load. Create a SubVar‘$_PS_Fz‘ with a value of,-50
kN. The minus sign is important because the force
direction is related to the Force Element‘sFrom
Marker: The guidance Marker must be ‘pulled‘ up-
wards, in negative z direction, in order to have the
wheel setpressed on the rails.
4.2. Wear analysis and results
For the test I used four new combinations of wheel
and rail materials and one material combination
with similar property with the Addis Ababa LRT
2. PROBLEM DESCRIPTION
Different countries like China, America, India and Ger-
man spend millions of dollars annually for repairing and
replacement of worn wheels and rails, for instance
America spent more than 900M dollars for wheel re-
placement in the year 2010-2011 and 32.2% of it is due
to wheel wear[6].
Researches show that improved rail materials like the
standard carbon steel grade R260 reduced wear rate sig-
nificantly when it replaced the R200 half a century ago.
Recently improved materials like AAR (Association of
American Railroad) classes, AAR Class C, AAR Class
B, and ER7 are widely used for the wheel and Thyssen/
Krupp60E1 for the rail [5].The purpose of this research
is to find a better material combination between wheel
and rail for further reduction of wear rate, which in turn
reduces a great amount of expense. For this research I
will develop a model using SIMPAK software to simu-
late an actual wheel/rail interaction condition. Many
researches like the one done by Roderik A Smith fo-
cuses on a new material for the wheel/rail and some oth-
ers perform a test for the wear behavior based on real
experimental setups. However, my research does not
aim to find for new sets of materials, instead I will per-
form a matching between the existing wheel and rail
materials and test for their wear behavior so that we can
identify the effective combinations of wheel/rail materi-
als with minimum wear rate.
3. APPLIED METHODS
The methods used to do this research are the following:-
Data collection and study on recently used wheel/
rail materials.
Vehicle modeling and simulation using SIMPACK
software.
Result analysis
4. MODELLING AND ANALYSIS
4.1. Vehicle Modeling Using Simpack
Fig.1. - Vehicle model
Ethiopian Society of Mechanical Engineers (ESME) - 20 -
Journal of the 21st Annual Conference May, 2017
TABLE 2
CHEMICAL COMPOSITION AND HARDNESS
4.2.4 Material properties and important inputs for the
SIMPACK vehicle model
TABLE 3
SELECTED WHEEL/RAIL GRADES AND THEIR
PROPERTIES
4.2.5 Input for the SIMPACK model The combined young‘s modulus [29]
Where:-
Ei is the young‘s modulus of material i.
Ej is the young‘s modulus of material j.
νi is the poisson‘s ratio of material I .
νj is the poisson‘s ratio of material j.
specifications (Material combination 0), the mate-
rial combinations used for this wear analysis are
presented as below.
4.2.1 Explanation on material combination
To make the concept material combination it is enough to see fig. 26 material combination implies simply a selection and matching of different standard of rail and wheels. It has no connection with mixing the materials of the wheel and rail chemically.
Fig.3. - Explanation of Material combination, example: - Material combination 0
4.2.2 Heat treatment of the five material combinations
TABLE 1
HEAT TREATMENT OF THE SELECTED MATERIALS
4.2.3 Chemical composition and hardness of the five material combinations
Ethiopian Society of Mechanical Engineers (ESME) - 21 -
Journal of the 21st Annual Conference May, 2017
Combination Wheel Rail
Material combination 0 Normalized Normalized
Material combination 1 Normalized Normalized
Material combination 2 Whole heat
treated (hard) Whole heat treated
(hard)
Material combination 3 Rim heat treated
(hard) Whole heat treated
( very hard)
Material combination 4 Normalized Whole heat treated
( very hard)
Material combination
Chemical composition %
Hardness
C Si Mn p S
Material com-
biantion0
Wheel 0.4 0.35 0.8 ≤ 0.05 ≤0.05 200
Rail 0.6 0.5 1.3 ≤0.05 ≤0.05 240
Material com-
biantion1
Wheel 0.4 0.3 0.8 ≤ 0.05 ≤ 0.05 220
Rail 0.6 0.1 1.3 ≤ 0.04 ≤ 0.04 260
Material com-
biantion2
Wheel 0.5 0.1 1.3 ≤ 0.025 ≤ 0.025 240
Rail 0.6 0.1 1.3 ≤ 0.03 ≤ 0.03 270
Material com-
biantion3
Wheel 0.6 0.1 1.3 ≤ 0.04 ≤ 0.04 260
Rail 0.8 0.1 0.8 ≤ 0.025 ≤ 0.03 350
Material
combiantion4
Wheel 0.6 0.35 0.8 ≤ 0.05 ≤ 0.05 200
Rail 0.8 0.1 0.8 ≤ 0.03 ≤ 0.03 350
(b) Fig. 5. -Maximum wear number for material combination 0,
(a) graphical representation and (b) SIMPACK output
TABLE 5
MAXIMUM WEAR NUMBER OF THE FIVE MATE-
RIAL COMBINATIONS
5.1.2 Wear rate calculation
Wear rate Kw (Iw) from equation (16)
TABLE 4
COMBINED YOUNG‘S MODULUS
Another important input for the SIMPACK model is the poisons ratio as described in the above table.
5. RESULT
5.1. Wear analysis result, Wear number (Wear index)Iw
Fig.4.- Wear results of the five material combinations using
SIMPACK
5.1.1. Maximum wear number (wear index)
(a)
Ethiopian Society of Mechanical Engineers (ESME) - 22 -
Journal of the 21st Annual Conference May, 2017
Material combination Combined young‘s
modulus (Gpa)
Material combination 0 224.3
Material combination 1 228.55
Material combination 2 229.45
Material combination 3 226.44
Material combination 4 225.71
Material combination Wear index (Iw),max ( N/mm2 )
Material combination 0 89.2698
Material combination 1 89.7228
Material combination 2 89.8164
Material combination 3 89.6633
Material combination 4 89.3419
1. INTRODUCTION
"FORTSCHRITT ELECTRO - MECHANICAL SERVICES PLC" /FEMS/
is established in 1997 by a group experienced pro-fessionals engaged in various Electro-Mechanical works and consultancy.
FORTSCHRITT ELECTRO-MECHANICAL SERVICE PLC (FEMS)
has participated in various technical activities throughout the nation. The company
still carrying out some projects located at different regions in the country.
Some of our works include:
Design, Installation, Rehabilitation and Maintenance of electro-Mechanical
works. Such as High Voltage Sub stations, Electrical Distribution networks,
Waste Water Treatment Plants Supply and installation of equipment for Ho-
tels, Hospitals and Factories,
Address: CETU building, Bole Road Room No 001/1
P.O.BOX 13574 Addis Ababa Ethiopia
Telephone: +251-111-550-9545 +251-111-550-3938
Email: [email protected]/[email protected]
Contact Person: Mr. Mulugeta Edea ö Managing Director
Cell Phone: +251-911-23666
2. Activities of the firm
Ethiopian Society of Mechanical Engineers (ESME) - 23 -
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) - 24 -
TABLE 6
WEAR RATE OF THE FIVE MATERIAL
COMBINATIONS
5.1.3 Specific volume of material removed
From equation (17)
TABLE 7 SPECIFIC VOLUME OF MATERIAL REMOVED
Fig.6. - Specific volume of material removed
5.2. Derailment coefficient The derailment coefficient is an indicator of the risk of derailment of the vehicle. It indicates the safety level of the vehicle.
Fig.7. - Derailment coefficient outputs
5.2.1 Maximum Derailment coefficient values
(a)
(b) Fig.8. - Maximum derailment coefficient of Material
combination 0. (a) Graphical representation and
(b) SIMPACK output
Journal of the 21st Annual Conference May, 2017
Combination Wear rate, Kw(µg/m
mm2 )
Material combination 0 802.8
Material combination 1 830.8
Material combination 2 836.6
Material combination 3 827.1
Material combination 4 807.2
Combination
Specific volume of material removed ( mm3/m mm2 )
Wheel Rail
Material combination 0 0.103
0.111
Material combination 1 0.107
0.106
Material combination 2 0.107 0.108
Material combination 3 0.105 0.106
Material combination 4 0.103
0.103
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) - 25 -
TABLE 8
MAXIMUM DERAILMENT COEFFICIENT VALUES OF
THE FOUR MATERIAL COMBINATIONS
Fig.9. Maximum derailment coefficient of the five material
combinations
5.2.1 Discussion on the derailment coefficient values
Fig.10. - Forces at flange and tread contact [30]
Q, vertical load Y, lateral reaction F, component of tangential force in the transverse verti-cal plane N, normal reaction
Explanation Derailment occurs when the vertical load Q is carried entirely by the point of contact on the flange, and so the derailment limit is defined by the minimum value of the lateral reaction Y.
We know that µ depends on the material in contact and it decreases as hardness increases. Which implies that the derailment coefficient is greatly affected by the hardness of the existing material of the wheel and the rail as can be seen from the SIMPACK simulation and the mathematical equation.
6. CONCLUSION
Generally, as the hardness of the rail, increase there is a better wear performance but in the case of wheel rail contact a better result is obtained when a rela-tively softer wheel material rolls on a relatively harder material.
Increasing hardness of both wheel and rail doesn‘t secure wear rate reduction
Specific volume of material removed highly depends on the density of the material combination not only on hardness.
Softer wheel material with rim heat treated performs better wear property when rolled on a harder rail.
Grade of material also affects the coefficient of fric-
tion that is necessary to keep the vehicle on track. We can see that material combination 0 has the best
wear performance for the wheel and material combi-nation3 has the best wear performance for the rail. But the combined effect of the wheel from material combination0 and rail from material combination3 gives a better result. However, as the hardness in-creases the cost of material increases because of the processes needed to attain high hardness, which makes the initial investment, as well as replacement cost expensive.
Combination Derailment coefficient
Material combination 0 0.351391
Material combination 1 0.3530 Material combination 2 0.353967
Material combination 3 0.353946
Material combination 4 0.35176
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) - 26 -
As a combination, among the simulated combina-
tions material combination4 is the best in terms of wear performance and have a good stability in terms of derailment.
REFERENCE
[1]. Roderick A Smith: ―Railway and materials‖, vol 35, no 7, 2007, pp 505.
[2]. S. Marich: ―Development of improved rail and wheel
materials‖, pp 23-27. [3]. MartinSchilke: ―Degradation of Railway Rails from a
Materials Point of View‖, 2013, pp3-9. [4]. Cameron Lonsdale,Prof. Roman Bogacz,Mark Norton:
Application of Pressure Poured Cast Wheel Technol-ogy for European Freight Service, world congress on railway research 2011.
[5]. Wolfgang Schoech, GregorGirsch, Rene Hey-
der:Advanced rail steel grades and their appropriate maintenance – the key to combat rcf, 2012.
[6]. ―18thannual Association of American Railroad (AAR)
research review‖, 2013. [7]. www.amstedrail.com. | +1.312.922.4501 | 311
S.Wacker Drive, Suite 5300, Chicago, IL 60606. : The global leader in railway wheels, 2012.
[8]. Pombo, J., Ambrosio, J., Pereira, M., Lewis, R., Dwyer
-Joyce, R., Ariaudo, C., Kuka, N. ―A study on wear evaluation of railway wheels based on multibody dy-namics and wear computation, Multibody System Dy-namics‖, (2010) 24 (3), pp. 347-366
[9]. K. Mädler, A. Zoll, R. Heyder, M. Brehmer :‖Rail Ma-
terials - Alternatives and Limits‖, Deutsche Bahn AG, DB Systemtechnik, Brandenburg-Kirchmöser, Ger-many
[10]. Venkatarami Reddy: Development of and Integrated
method for assessment of operational risks in rail track. [11]. 22nd International Symposium on Dynamics of Vehi-
cles on Roads and Tracks (IAVSD2011), Manchester, UK, August 14-19, 2011
[12]. Benson, M. (1993) Effect of differential hardness on
wheel/rail wear0 literature survey, BRR report LR MT 006, September 1993
[13]. Bolton, P. J. (1981) ―Wear of six rail steels in rolling/
sliding contact with Class D tyre steel. BRR report‖ TM MF 20, November 1981
[14]. McEwen, I. J. (1986) ―A review of laboratory-based
wheel on rail wear studies carried out by the vehicle track interaction unit. BRR report TR" VTI 003, March 1986
[15]. Singh, U. P., Singh, R. K. and Mangal, R. K. (1992)
―Investigation of wheel and rail wear under conditions of sliding and rolling-sliding contact‖. 10th Interna-tional Wheelset Congress, Sydney, Australia, October 1992
[16]. Marich, S. and Curcio, P. (1978) ―Development of high
strength alloyed rail steels suitable for heavy duty ap-plications. Rail steels developments, processing and use‖, ASTM STP 644, 1978
[17]. The abrasive wear of wheel and rail steels and their
inter dependence laboratory tests. British Steel Corpo-ration Research Report SH/PROD/ENG/9422/-/81/B,
April 1981. [18]. Mädler, K., Zoll, A., Heyder, R. and Brehmer, M.
(2001) ―Rail materials alternatives and limits‖. Proc. 8th World Congress on Railway Research (WCRR), Seoul, Korea, May 2008
[19]. Vasic, G. and Franklin, F. (2011) ―Plastic deformation
and crack initiation in hard pearlitic rail steels‖. Proc. ―21st Century Rail‖, The Institute of Materials, Miner-als and Mining, York, UK, November 2011
[21]. Katrin Mädler, Manfred Bannasch Deutsche Bahn AG,
―Materials used for Wheels on Rolling Stock‖, Tech-nical Centre, Brandenburg-Kirchmöser, GERMANY
[22] ―Vehicle System Dynamics‖: International Journal of
Vehicle Mechanics and Mobility Publication details, including instructions for authors and subscription in-formation.13 Jun 2012.
[23]. J Santamaria, J. Herreros, E.G. Vadillo, N. Correa,
―Design of an optimised wheel profile for rail vehicles operating on two track gauges‖ . Department of Me-chanical Engineering. University of the Basque country UPV/EHU. Alameda Urquijo s.n., 48013 Bilbao, Spain.
[24]. Addis Ababa LRT Project North-South line project
study report, China railway group limited, 2009. [25]. David C. Grundy, B.S., Fatigue and fracture of Rail-
way wheel Steel, University of Pittsburgh (1991). [26]. ―Design Technologies for Railway Wheels and Future
Prospects‖, NIPPON Steel & Sumitomo metal techni-cal report no. 105 December 2013.
[27]. ―Modern Traibology Hand book‖. 2001,Chap. 34. [28]. ―Improved model for the influence of vehicle conditions
(wheel flats, speed, axle load) on the loading and sub-sequent deterioration of rails‖, Newcast Univer-sity,september 2006.
[29]. SIMPACK Documentation, Release 9.3, 2013. [30]. A.H. Wickens, Fundamentals of Vehicle dynamics
Guidance and Stability, University of UK, 2003
Ethiopian Society of Mechanical Engineers (ESME) - 27 -
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) - 28 -
I. INTRODUCTION
Railway transportation is attracting attention as an ef-
fective means of modal shift in transportation. Cur-
rently; electrified railway system has vital environ-
mental advantages that are becoming significant as
concern about climate change grows.
With technological advancements of electric railway,
speed up of train, prolonging lifetime and reducing
maintenance cost of the overhead contact wire are com-
pulsory. Major efforts have devoted to solve these is-
sues to meet the expectations of stakeholders. The prop-
erties of the contact wire are of the basic factors that
greatly affect the speedup of the train and the cost
of maintenance. To improve the quality of the con-
tact wire, wear resistance and corrosion resistance of
the material should be enhanced.
To withstand the harsh service condition in real applica-
tion, the electric contact wire made with the new mate-
rials should possess high hardness and mechanical
strength, high sliding wear and corrosion resistance and
good electrical conductivity.
A poor contact produces various drawbacks, including
bursts of arcing: if they have a long duration, locomo-
tive efficiency may reduce and an excessive wear of
the pantograph strips and of the contact wire may
lead to maintenance problems, up to crashing of cate-
nary [5]. Excessive wire wear can lead to breakage
causing the service to be suspended it will results main-
tenance cost. The costs linked to a service being sus-
pended can be extremely high, although the most im-
portant factor is the consequence on the passengers af-
fected so it has socio economic impact.
In the new network rail transport in Ethiopia if these
problems are not analyzed from the beginning and ig-
nored, it will cost more in incidents, accidents, fatality
and excess maintenance cost. Therefore, it is very im-
portant to find a compromise that will allow maximum
usage of the wire without entailing any risk of breakage
and major efforts have been devoted to prolonging the
lifetime and reducing the maintenance costs of the
overhead catenary.
Addis Ababa Light Rail Transit uses Cu-Ag contact
wire and pure copper supports, but their contact wire
material has poor wear and corrosion resistance. Since
our country is introducing this technology, the contact
wire line system shall be characterized of safe and reli-
able performance, being able for satisfy the operation
requirements at the maximum operation speed of 80km/
h and in various environmental conditions. The aim of
present study is to develop the overhead contact wire
materials that have relatively better wear and corrosion
resistance with low cost and good electrical conductiv-
ity.
Journal of the 21st Annual Conference May, 2017
Development of Train Overhead Contact Wire Material
Ashreka Yenus1, Dr. Daneil Tilahun2 1School of Industrial and Mechanical Engineering, Addis Ababa University Institute of Technology (AAIT),
Addis Ababa, Ethiopia 2 School of Industrial and Mechanical Engineering, Addis Ababa University Institute of Technology (AAIT).
Addis Ababa, Ethiopia
Abstract - The paper aimed at developing overhead contact wire material (Cu-Ni-Cr), which has better slid-
ing wear and corrosion resistance with moderately low cost, in view of the current Addis Ababa Light
Rail Train overhead contact wire (Cu-Ag). The sliding wear resistance, corrosion resistance and electrical
conductivities of the prepared copper alloys were investigated by using lab testing machines. The character-
istics of worn surfaces of the copper alloys were analyzed by optical microscope. The dominated wear mecha-
nisms are abrasive and adhesive wear in mechanical sliding frictional process. Among the copper alloys inves-
tigated, Cu- Ni-Cr which possesses highest corrosion resistance, quite good electrical conductivity and rela-
tively high wear resistance (two times that of Cu-Ag). Based on the findings obtained in this work, it is sug-
gested that Cu-Ni-Cr is found to be suitable for Addis Ababa light rail train and future national railway
overhead contact wire. However further investigation is needed with the application of electric current.
Keywords: Overhead contact wire, Sliding wear, Corrosion, Electrical conductivity
Ethiopian Society of Mechanical Engineers (ESME) - 29 -
II. LITERATURE REVIEW
The contact wire serves as a medium through which
electricity is supplied to the train using sliding contact
with pantograph of rolling stock. Both mechanical and
electrical considerations have to be acknowledged
when choosing material of the contact wire [1]. The
overhead contact wire is subjects to friction and corro-
sion at different degrees of severity depending on the
wire materials and the environmental conditions. Simi-
larly external influences such as wind and humidity
can ha ve an effect on the rate of contact wire wear [4].
The wear behaviors of tribological pairs with electrical
current were different from those without electrical cur-
rent [8].Wear is due to mutually related mechanical and
electrical factors. According to[10],the most influen-
tial factors are the material and collector strip are made
of, the contact force, the current intensity and the
speed of the vehicle. Irregularities in the wire and par-
ticularly singular spots with local variations in stiffness
cause contact losses between the pantograph and the
catenary, [10], [11], [12], and [13]. These accelerate
the wear process at a local level.
The over head contact wires are designed to give high
resistance to wear, corrosion and have good electrical
conductivities to prolong service life. Copper alloy con-
ductors are preferred instead of pure copper [2].There
are different researchers who have conducted on devel-
oping and improving materials for train overhead con-
tact wire by considering their electro mechanical prop-
erty. Among those researches; the paper on the
―Sliding wear behavior of copper alloy contact
wire against copper-based strip‖ they developed
CuAg Cr alloy in order to compare to that of Cu Ag
alloy. Finally; they found that the Cu Ag Cr alloy wire
had much better wear resistance because of the addi-
tion of Cr [3].
In Ethiopia, due to the early establishment of rail-
way engineering sector there is a shallow or few
researches have been done on railway area. Specifi-
cally, on development of train over head contact
wire material, there is a huge gap of conducted research
in the area. Therefore this study is expected to reduce
this gap.
III. RESEARCH METHODOLOGY
For this experimental investigation, four industrial grade
materials like Cu, Ni, Cr and Si were collected from
Aka ki basic metals, Elsewdy cables and Gafat. The ma-
terials have chosen by considering both mechanical and
electrical properties. Table1 shows wear resistance, cor-
rosion resistance, hardness and electrical conductivity of
selected materials.
After having the appropriate materials to get the needed
percentage composition, calculation was conducted. The
chemical composition of copper alloys before melting
process is presented in Table 2 below. Following
amount preparation the melting process was carried out
by graphite crucible with oil furnace at Yalew garage.
The materials were melted according to their melting
temperature. Finally; Pins of diameter of 13 mm and
length of 13 mm were prepared by lathe machine at the
Mechanical Workshop of AAiT. As a sample, Fig.1
shows the copper alloy pins Cu-Ni-Si-Cr and Cu-Ni-Cr
after melting and machining process. With collaboration
of Hebert Manufacturing Industry, the chemical compo-
sition and hardness of the prepared copper alloys were
obtained by using spectrometer and Vickers hardness
testing machine respectively.
Sliding wear, corrosion and electrical conductivity of
the copper alloys were tested by lab testing machine in
the department of Mechanical, Chemical and Electrical
Engineering laboratory respectively.
(a)
(b)
Fig.1. - Photographs of the copper alloy pins after melting and
machining process
Journal of the 21st Annual Conference May, 2017
Cu - Ni - Si - Cr
Cu - Ni - Cr
test. The test was con-
ducted by corrosion
studies kit and the cop-
per alloys were embed-
ded in pure distilled
water, 3.5%Nacl solu-
tion and acid rain solu-
tion for 3 to 10 days.
After the experiment has
been comple- ted, re-
weighed the specimen and Put the gram difference
which indicates the corrosion part.
3. Electrical Conductivity Test
After knowing t h e chemical composition
and later the hardness test and the electrical
conductivity test was conducted at room
temperature .The resistance value of the four
copper alloys measured with the help of mul-
timeter from these value the resistivity and
conductivity value of the alloys can be
found.
V. LABORATORY TEST RESULTS
AND DISCUSSION
1. Sliding Wear Behavior
The plot of wear resistance with different normal
forces under constant velocity and time is shown in
Fig.2 below. The graph shows the wear resistance prop-
erty of each material. Among the copper alloys Cu-Ni-
Si-Cr has highest wear resistance followed by Cu-Ni-Cr
and Cu-Ni-Si. Cu-Ag possesses the lowest wear resis-
tance. Moreover, the graph shows when the force in-
creases the wear resistance of all material decrease be-
cause of high friction at the contact. The ranking of
sliding wear resistance at 3.5N, 5.5N and 7.5N and
at constant velocity in descending order is; Cu-Ni-Si-
Cr>Cu-Ni-Cr>Cu-Ni-Si>Cu-Ag. Cu-Ag has highest
wear rate followed by Cu-Ni-Si .The copper alloy Cu-
Ni-Si-Cr has lowest wear rate. Addition of elements
such as Cr, Ni and Si to copper significantly im-
proves the hardness and hence the wear resistance also
increases. Compared with CuAg, the wear resistance
was increased by 3 and 2 times for CuNiSiCr and
CuNiCr respectively. In general, the wear resistance of
the Cu based alloys increases with the increase in hard-
ness.
Source: Copper Development Association TABLE 1
PROPERTIES OF SELECTED MATERIALS FOR THIS
STUDY
TABLE 2
CHEMICAL COMPOSITION OF COPPER ALLOYS USED
FOR THE STUDY
IV. LABORATORY TESTS AND CONDITION
1. Sliding Wear Test
Sliding wear tests of the alloys were conducted using a
pin-on-disc tribometer which simulated the tribological
conditions of sliding contact strip on overhead wires in
the railway system. The copper-alloys in the form of
cylindrical pins were forced to slide against a stainless
steel disc with a sliding velocity of 80 km/h at room
temperature under un-lubricated condition and normal
load up to 11N without electric current. The amount of
wear is determined by weighing the specimen before
and after the test using precession electronic weighing
machine. The worn surface and wear debris of the se-
lected specimen after sliding wear test were then ana-
lyzed by optical microscopy.
2. Corrosion Test
In order to simulate acidic and costal environmental
conditions the corrosion test was carried out with
3.5%NaCl solution, acid rain solution with 5PH and
distilled water under room temperature, while the cur-
rent supply to the solution ended constant throughout the
Ethiopian Society of Mechanical Engineers (ESME) - 30 -
Journal of the 21st Annual Conference May, 2017
Material Hardness Wear
resistance
Resistance to
corrosion
Electrical
conductivity
Cost
Copper low low low very high moderate
Chromium very high very high good good high
Nickel high high very high moderate low
Silicon good good high moderate higher
Material
Chemical composition in %
Cu Si Cr impurities
Cu -Ni-Si-Cr 96.7with0.04% O2 2.4 0.003 0.077 <0.78
Cu-Ni-Si 99 with0.04% O2 0.503 0.14 <0.317
Cu -Ni-Cr 98.6with0.04%
O2
0.33 - 0.193 <0.837
Cu-Ag (99.3Cu-0.08Ag) as per specification of ERC
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) - 31 -
(b)
(c)
(d)
Fig.3. - Photographs of worn surfaces of (a) Cu-Ag;(b) Cu-
NiSi ;(c) CuNiSiCr and (d) CuNiCr With load of 7.5N
In this Experiment, for the harder material which is
CuNiSiCr, the size of the wear debris is much smaller
as shown from the figure 3(c) and the smaller wear
particles were removed from the CuNiSiCr specimen
after the wear test and a lower degree of scratch is
observed .CuNiCr has also a good wear resistance the
size of the fragment is small as shown in figure 3(d)
so CuNiCr harder compare to Cu-Ni-Si and Cu-Ag.
Fig.2. - Plot of wear resistance versus applied load
2. Mechanism of Sliding Wear
The worn surfaces of the specimens were observed
by optical microscope. Figure below shows the
worn surface of copper alloys without the electrical
current under load of 7.5N at the sliding speed of
80km/h for 2 minute respectively. Friction is the
main factor of mechanical wear when the alloys
slide without electric current which includes abrasive
and adhesive wear mechanism.
On micro-scale, asperities of the harder surface press
into the softer surface, with plastic flow of the softer
surface occurring around the harder asperities. The de-
tached mixture of metal and oxide debris acts as the
hard abrasive and causes abrasive wear. For adhesive
wear, the asperity junction of the sliding surfaces of
counter parts under normal contact force adhered to-
gether.
(a)
Ethiopian Society of Mechanical Engineers (ESME) - 32 -
Journal of the 21st Annual Conference May, 2017
RECOMMENDATION It is better to consider service life of contact wire
for future work since the overhead contact wire is
subjects to abrasion, friction, scraping, corrosion,
erosion and vibration, at different degrees of sever-
ity.
For Addis Ababa light rail project and future na-
tional railway, it is suggested that for the future by
making further investigation with the application of
electric current , they can use this Cu Ni Cr material
as the over head contact wire.
At acid rain solution the corrosion effect is high so
in order to promote safety issue that related to corro-
sion failure of overhead contact wire while im-
plementing the project it is necessary to have pro-
tected environment beyond the contact wire material
property.
REFERENCES
[1] Po Kee Wong, Chi Tat Kwok, Hau Chung Man,
and Fai Tsun Cheng. (2009), Electrical Sliding
wear of copper-based contact wire materials for
electric railway, International Symposium on
Speed-up, Niigata Japan.
[2] Kwok, C.T., Wong, P.K., Man, H.C. and Cheng,
F.T.(2010),Sliding Wear and Corrosion Resis-
tance of Copper-based Overhead Catenary for
Traction Systems, IJR International Journal.
[3] Jia a, S.G., Liua, P., Rena, F.Z., Tian a, B.H.,
Zheng b, M.S. and G.S. Zhoub.(2006), Sliding
wear behavior of copper alloy contact wire
against copper-based strip for high- speed elec-
trified railways, School of Materials Science
and Engineering,Henan University of Science and
Technology, China.
[4] Delhi Metro Rail Corporation Ltd, pre feasibility
report.(2011), Power Supply and Overhead Cate-
nary System.
[5] Aldo Balestrino, Ottorino Bruno, Alberto Landi,
Luca Sani.(2005), Active Controls and Non-
Invasive Monitoring for High Speed Trains,via
Diotisalvi 2, 56126, Pisa, Italy.
[6] China railway publishing house.(2005), Copper and
copper alloy contact wires for electric railway, TB/
3. Corrosion Behavior The plots of weight loss in grams with different corro-
sion Medias are presented in Fig.4. From the graph be-
low the corrosion effect is highest at acid rain solution
followed by 3.5%Nacl solution. The high weight loss
indicate the high corrosion rate and the low corrosion
resistance property of the material. From the ranking of
corrosion resistance for the corrosion Medias, Cu –Ag
is highly corroded followed by Cu-Ni-Si. Cu-Ni-Cr
has highest corrosion resistance.
Fig.4. - Plot of Corrosion media versus weight loss
VI. CONCLUSION AND RECOMMENDA-
TION
CONCLUSION
Based on the laboratory test results, the investiga-
tion into the electrical conductivity, the behavior of
wear generated by sliding friction (mechanical wear)
under conditions of varying normal load and constant
sliding speeds and the corrosion behavior of copper
alloys under 3.5% Nacl solution, acid rain solution and
distilled water by electro chemical method finally have
led to the following conclusions.
Adhesive wear and abrasive wear are the wear
mechanisms during the mechanical sliding which
results in metal transfer, removal, debris genera-
tion and surface deterioration.
The ranking of sliding wear resistance in descending
order is :CuNiSiCr> CuNiCr>CuNiSi>CuAg.
Among the alloys Cu-Ni-Cr has the highest cor-
rosion resistance and also takes less purchase
cost.
Among the corrosion media, High corrosion
effect observed in PH5 acid rain solution.
The wear resistance of the copper- based alloys
increases with decrease in normal load.
Ethiopian Society of Mechanical Engineers (ESME) - 33 -
Journal of the 21st Annual Conference May, 2017
T 2809-2005, china.
[7] Copper development association. (2010), A guide
to working with copper and copper alloys,
collection of scientific research from 1990-2009,
New York.
[8] Herbert Henry ,Uhlig. (2008),Corrosion and Corro-
sion Control: an introduction to corrosion sci-
ence and engineering, R Winston Revie:-4th Ed.
[9] Gonzalez, F.J., Chover, J.A., Suarez, B. and
Vazquez, M.(2008), Dynamic analysis using
finite elements to calculate the critical wear sec-
tion of the contact wire in suburban railway
overhead conductor rails, Journal of Rail and
Rapid Transit, Vol. 222, pp. 145-157
[10] Collina,A., Melzi, Stefano and Facchinetti,A.
(2002), On the Prediction of wear of contact
wire in OHE lines: a proposed model, Vehicle
System Dynamics Supplement Vol. 37,
pp. 579-592.
[11] Bruni, S., Bucca, G., Collina, A., Facchinetti,
A.and Melzi,S.(2004) PantographCatenary
Dynamic Interaction in the Medium-High Fre-
quency Range, Vehicle System Dynamics
Supplement Vol. 41, pp. 697-706.
Ethiopian Society of Mechanical Engineers (ESME) - 34 -
Journal of the 21st Annual Conference May, 2017
commuter rail stations vis-a`-vis those occurring at
highway rail grade crossings with attached sidewalks.
Furthermore, incidents in crossings with commuter rail
or light rail would require different countermeasures
than those occurring in crossings with freight rail. A
large array of treatments has been applied in different
rail grade crossing environments to improve the safety
of non-motorized users, but their effectiveness remains
difficult to assess [26]. This paper will highlight the-
matic areas related to pedestrian safety at rail grade
crossings that are primed for further research and policy
intervention. The presentation will synthesize literature
findings. The objective of the paper is to offer informa-
tion for researchers and practitioners involved with
safety at rail grade crossings.
II. LITERTURE REVIEW
In this paper, the terms ‗pedestrian,‘ ‗non-
motorists ‘and‗ non-motorized users‘ will be used inter-
changeably to indicate crossing users who utilize pedes-
trian approaches to rail grade crossings. Such users in-
clude (obviously) pedestrians, pedestrians pushing a
stroller, cyclists (either on bike or off their bike), and
users on wheelchair using an exclusive pedestrian ap-
proach to a rail grade crossing.
The literature findings will discuss issues with warning
devices, accessible non-motorist signals, engineering,
Ethiopian Society of Mechanical Engineers (ESME) - 35 -
Journal of the 21st Annual Conference May, 2017
I. INTRODUCTION
The number of fatalities due to train–vehicle collisions
at highway-rail grade crossings, the number of non mo-
torist fatalities at rail grade crossings has increased.
However the number of pedestrian fatalities has in-
creased. Advancing pedestrian safety at rail grade cross-
ings is a challenging issue for many reasons. Pedestrian
crossing incidents occur in different settings requiring
the coordination of different stakeholders with context-
sensitive solutions. For example, incidents involving
violations at rail grade crossings are different from tres-
passing incidents away from such crossings. Note that
violations in this context can occur in three occasions
[33, p. 28]: (a) when a pedestrian enters the crossing
when the warning lights are flashing but before the gate
arms have begun to move; (b) when a pedestrian enters
the crossing when the gate arms are in motion, either in
their descent (before train arrival) or ascent (after train
departure); and, (c) when a pedestrian enters the cross-
ing after the gate arms are in their horizontal position.
On the other hand, trespassing incidents involve indi-
viduals who are trespassing on railroad rights-of-way at
locations other than authorized grade crossings, includ-
ing overhead and underground crossings. Other contex-
tual distinctions regarding pedestrian crossing incidents
may include those at crossings that are exclusively used
by non-motorists in the vicinity of or within the area of
Pedestrian Safety at Rail Grade Crossings
Er. Prakash C.H Lecturer, Department of Mechanical and Vehicle Engineering, Adama Science and Technology University,
Adama, Post Bag 1888, Ethiopia, [email protected]
Abstract - The number of fatalities due to train–vehicle collisions at highway-rail grade crossings, the number
of pedestrian and bicycle fatalities at highway- and pathway-rail grade crossings has increased in the last
dozen years. While engineering solutions and education and enforcements initiatives have been proposed and
implemented, little is known as to their effectiveness to mitigate such incidents. This paper reports on safety at
rail grade crossings. Major areas that in need for improvement include (a) advancing consistent standards for
warning devices and treatments; (b) advancing consistent approaches for managing non-motorist risk; and (c)
continuing commitment to education, engineering, enforcement, and evaluation efforts by enabling stake-
holders to provide adequate resources. The paper highlights the multitude of factors related to pedestrian
safety in this context, and provides information for researchers and practitioners involved in advancing safety
initiatives.
Key words- Pedestrian Safety, rail grade crossing, highway grade crossing
crossing and (b) the number of pedestrians entering the
track area at 6 s or less before a train entered the cross-
ing with the flashers activated, a much riskier behavior.
The study compared pedestrian behavior before and af-
ter installation and found that the installation of the sig-
nal reduced the incidence of risky pedestrian behavior
by 14 % on the first benchmark and 32 % on the second
one.
B. Accessible Non-motorist Signals
Accessible pedestrian signals (APS) are devices that
communicate information about pedestrian timing in
non- visual formats such as audible tones, verbal mes-
sages, and/ or vibrating surfaces (MUTCD, Section
4A.01) [36]. According to a synthesis on best practices,
the new type of APS available can provide information
to pedestrians about the existence and location of the
pushbutton using audible tones; the onset of the walk
interval using a vibrotactile indication; the direction of
the crosswalk and location of the destination curb using
different audible tones for north/south and east/west
directions; the clearance interval using audible tones;
intersection geometry through maps, diagrams, or
speech; intersection street names in Braille, raised print,
or speech; and intersection signalization using a
pushbutton information message.
A description of these features is given in a series of
reports produced by Project 3-62, ‗‗Guidelines for Ac-
cessible Pedestrian Signals of the National Cooperative
Highway Research Program‘‘ [13–15]. Additional pub-
lished guidelines are provided by the U.S. Architectural
and Transportation Barriers Compliance Board [35].
APS at rail grade crossings may assist disabled pedestri-
ans with making better judgments in regard to safely
crossing the tracks at rail grade crossings. However,
research about APS use in such environments is limited.
Indeed Korve Engineering [20] found only limited re-
search testing APS under field conditions in LRT envi-
ronments and no additional research other than Blasch
[4] comparing the effectiveness of different APS in nor-
mal traffic conditions.
The study found there was a significant difference re-
garding their utility to provide a line of direction for
street crossing, but no significant differences in regard
to confidence and comfort of the user.
In addition, in the United Kingdom, Delmonte and Tong
[9] conducted a comprehensive analysis to identify solu-
Ethiopian Society of Mechanical Engineers (ESME) - 36 -
Journal of the 21st Annual Conference May, 2017
education and enforcement, engineering standards and
guidelines, intelligent grade crossings, and cost consid-
erations. Such issues have received considerable atten-
tion and remain central in the discussion of pedestrian
safety but, to our knowledge, have never been presented
in a systematic manner. It would be worth noting that
other important relevant issues not frequently found in
the literature but identified by collecting secondary in-
formation from experts.
A. Warning Devices
In an effort to ‗‗foster the exchange of information
among and experiences among transportation agencies
and organizations that are involved with pedestrian
crossings of railroad tracks,‘‘ the Federal Railroad Ad-
ministration (FRA) compiled a report [37] on deployed
pedestrian safety devices at grade crossings that are not
included in the Manual on Uniform Traffic Control De-
vices (MUTCD). The report discusses both active and
passive devices. Active devices change their appearance
or position as soon as they receive a signal that a train is
approaching from a train detection system. Passive de-
vices do not change their appearance or position.
Examples of active devices discussed in the report in-
clude audible/visual devices, such as low-rise flashing
pedestrian signals and multi-use path flashing light sig-
nals; short gate arms; and second train coming elec-
tronic warning signs. Examples of passive devices in-
clude highly reflective passive warning signs and chan-
nelizing devices, such as different types of fencing,
swing gates, and zigzag or Z-gates. According to the
report, various factors that should be examined during
device selection include (a) collision experience, if any,
at the crossing, as it involves pedestrians; (b) pedestrian
volumes and peak flows, if any; (c) train speeds, num-
bers of trains, and railroad traffic patterns, if any; (d)
sight distance that is available to pedestrians approach-
ing the crossing; and (e) skew angle, if any, of the cross-
ing relative to the railroad tracks.
A study evaluated the (preliminary) effects on pedes-
trian behaviour of the installation of a second train
warning train activated signal at a highway-rail crossing
near the Vernon Avenue Station on the Los Angeles
County Metropolitan Transportation Authority‘s Metro
Blue light rail transit line [19]. The pedestrian sidewalk
crossed two light rail transit (LRT) tracks and two
freight rail tracks. Two measures of pedestrian behavior
were examined: (a) the number of pedestrians entering
the track area at 15 s or less before a train entered the
ance is provided by the MUTCD (Part 8) [36], Ameri-
can Railway Engineering and Maintenance of Way As-
sociation (AREMA) Communications & Signal Manual
[2], and Code of Federal Regulations 49 (Part 234). In
addition, the FHWA‘s Handbook [27] identifies pedes-
trian crossing treatments and provides recommendations
for flashing light signals, second train coming signals,
dynamic envelope markings, pedestrian automatic gates,
swing gates, bedstead (maze) barriers, z-crossing chan-
nelization, and combined pedestrian treatments.
Different standards apply to at-grade crossings of LRT.
LRT has at least five different categories of operational
alignments all of which have criteria for the type of
warning systems needed at intersections based on the
maximum operating speeds. Usually at speeds under 35
mph, LRTs use the existing street traffic signal controls
in conjunction with priority and pre-emption controls
[23]. At speeds above 35 mph, Active Warning Railroad
systems are used in conjunction with adjacent traffic
signal controls [21]. Additional guidelines for improv-
ing pedestrian and motorist safety along LRT align-
ments are reported in [8].
In California, CalTrain developed their own design cri-
teria regarding grade crossings and began implementing
them in 1999 [6]. These standard practices utilize active
warning devices similar to those at vehicular crossings:
signal equipment modified from that of vehicular cross-
ing, crossing gate arm, and a crossing configuration
which channels pedestrians. Different design criteria
apply for pedestrian crossings in general regarding
warning time, center fence, warning devices, safety
buffer zone, warning assemblies, gate recovery, as well
as pedestrian crossings at stations, at stations and road-
way, and crossings between roadway crossings.
The American Public Transportation Association
(APTA) provides guidance for rail transit systems for
selecting, installing, and operating highway-rail transit
grade crossing warning systems and includes minimum
requirements for highway-rail grade crossing warning
devices, highway traffic signs, and other highway traffic
control appliances [1]. Particular recommendations are
made for pedestrians at rail grade crossings.
The California Public Utilities Commission (CPUC) has
published extensive design guidelines for pedestrian-rail
crossings within the state of California [5]. Their review
of design considerations and installations includes rec-
ommendations for swing gates, detectable warnings, and
Ethiopian Society of Mechanical Engineers (ESME) - 37 -
Journal of the 21st Annual Conference May, 2017
tions for improving safety and accessibility at grade
crossings for disabled pedestrians. More specifically,
the study conducted discussion groups with disabled
pedestrians, scored and ranked potential solutions, and
developed an industry-approved set of solutions. The
most promising solutions were grouped to create an
‗ideal‘ accessible grade crossing. However, these solu-
tions have not been field tested yet.
C. Engineering, Education, and Enforcement
Under the Rail Safety Improvement Act of 2008 (P.L.
No.110-432), the U.S. Department of Transportation has
developed model railroad trespassing, vandalism, and
highway-rail grade crossing warning device violation
prevention strategies to assist State and local govern-
ments, and railroads. These strategies fall under three
broad categories: (1) expanding educational outreach,
(2) energizing enforcement, and (3) fostering engineer-
ing and sight improvements. Educational outreach in-
volves public awareness programs helping non-
motorists to safely navigate grade crossings. Consistent
enforcement of traffic safety laws by State or local po-
lice and a sustained effort by the courts to impose penal-
ties on violators discourage and deter non-motorists
from making poor decisions at grade crossings. A recent
report has published the latest compilation of state laws
and regulations affecting highway-rail grade crossings
[17]. Moreover, engineering improvements greatly re-
duce or prevent the potential for non-motorist-train col-
lisions [38]. Finally, Fitzpatrick et al. [10] presents addi-
tional discussion about engineering treatments for light
rail, commuter rail, and streetcar rail services.
The Illinois Commerce Commission (ICC), and the
FRA initiated the Public Education and Enforcement
Research Study (PEERS) to measure the before and af-
ter change in the public‘s adherence to traffic safety
laws [33]. The study demonstrated a reduction in cross-
ing violations and a dramatic reduction in the most dan-
gerous pedestrian behaviour. Moreover, Khattak and
Luo [18] found there is a need for pedestrian and bicy-
clist outreach and education, especially for children 8
years old or younger. In addition, Lobb [25] suggested
that lessons learned about behaviour and consequences
from cognitive psychology may apply to pedestrian
safety at rail grade crossings.
D. Engineering Standards and Guidelines
The Federal Highway Administration‘s (FHWA‘s) Rail-
road- Highway Grade Crossing Handbook [27] provides
guidance about pedestrian crossings. Additional guid-
guidelines, intelligent transportation technologies. To
the extent that such issues would need to be addressed
whenever new safety treatments are being planned, de-
signed, implemented, and evaluated, it is also clear that
very few, if any, studies have delved into these issues in
a holistic manner.
F. Initiatives for researches
The Problems that need to be concentrated by research-
ers and practitioners involved in advancing safety initia-
tives are:
What types of non-motorist safety treatments have to
be installed at rail grade crossings?
What types of APS have to be designed and in-
stalled?
What information to be collected on cost estimates
and/or actual costs of the warning systems that have
already installed?
How to evaluate the cost effectiveness of such safety
treatments?
What criteria need to be for the selection of warning
devices for deployment?
What engineering standards and guidelines have to
be applied to such crossings?
What are the educational outreach activities (e.g.,
public awareness programs, partnerships with other
organizations, etc.). How effective are they?
What are the enforcement initiatives (e.g., police,
courts). How effective are they?
What is the overall budget for safety at grade cross-
ings? For pedestrian safety?
The percentage of cost breakdown among engineer-
ing, education, and enforcement activities?
What funding sources to promote pedestrian safety at
rail crossings?
What are the policies/warrants/standards for using
warning signs for non-motorized users at rail grade
crossings (e.g., minimum warning times at/near to/
far from commuter stations, design/installation/
operational guidelines, etc.)?
What state and local regulations in addition to federal
regulations apply to non-motorized users at rail grade
crossings in your area?
III. FOCUS AREAS FOR IMPROVING PEDESTRIAN
SAFETY
A. Prioritization of Safety Upgrades
The safety upgrades at dedicated pedestrian crossings
are not prioritized as highly as those at rail-highway
Ethiopian Society of Mechanical Engineers (ESME) - 38 -
Journal of the 21st Annual Conference May, 2017
pedestrian gates, flashing light signal assemblies, sign-
age, crossing surfaces, channelization design, and other
treatments. Signage must conform to the state MUTCD.
The report makes a particular reference to the Transpor-
tation Research Board‘s Transit Cooperative Research
Program (TCRP) Report 69 Section 3.8.3 [21] which
provides a decision tree as a tool to determine appropri-
ate pedestrian rail at-grade crossing treatments. In addi-
tion, a risk-scoring methodology to evaluate safety fac-
tors at station pedestrian crossings is in use in the
United Kingdom [34].
A risk assessment methodology for pedestrian grade
crossings is part of the Australian Level Crossing As-
sessment Model (ALCAM) still under development [11,
32]. The model is an assessment tool used to identify
key potential risks at level crossings and to assist in the
prioritization of railway level crossings according to
their comparative safety risk. ALCAM uses a scoring
algorithm which considers each level crossing‘s physi-
cal properties (characteristics and controls) including
consideration of the related common human behaviors,
to provide each level crossing with a ‗‗Likelihood Fac-
tor‘‘ score. This score is then multiplied by the level
crossings ‗‗Exposure‘‘ score (a factor taking into ac-
count the volumes of Vehicles/Pedestrians and Trains)
and finally multiplied by the Consequence score (which
is set to be one for pedestrians) to give the ALCAM
Risk Score.
E. Intelligent Grade Crossings
Interesting new developments in the area of Cooperative
Intelligent Transportation Systems (ITS) may bring to
bear applications that could dramatically affect safety
for non-motorized users in grade crossings in the not so
distant future. Vehicle-to-vehicle (V2V), vehicle-to-
infrastructure (V2I), and vehicle-to-consumer devices
(V2D) are being developed to deliver more safety mo-
bility benefits. Pedestrians and non-motorized users, in
general, at rail grade crossings will be able to receive
personalized advance warning of incoming trains in
time to avoid injuries and fatalities.
Synthesis
It is evident from the previous literature review that
there is a considerable body of research that has studied
several dimensions of the problem regarding improving
pedestrian safety at rail grade crossings. These research
efforts have investigated issues with warning devices,
accessible nonmotorist signals, engineering, education
and enforcement strategies, engineering standards and
crossing, skew angle of the crossing relative to the rail-
road tracks, multiple tracks, vicinity to a commuter sta-
tion, and installation/maintenance costs. Furthermore, to
discourage trespassers at or in the vicinity of grade
crossings, communities apply fencing, landscaping, pro-
hibitive signs, video monitoring, education/outreach,
and enforcement.
D. Lack of Accessible Pedestrian Signals
The lack of APS at pedestrian-rail grade crossings is
mainly due to the shortage of dedicated funding for such
crossings. Such signal treatments need not convey the
type of messages needed in regular intersection street
crossings with more complicated traffic patterns. Occa-
sionally, there are situations in grade crossing improve-
ment projects where certain options are not available.
For example, in the absence of adequate right of way, it
usually becomes impossible to produce accessible side-
walks of the proper width in compliance with the
Americans with Disabilities Act (ADA) standards. An-
other reason for the infrequent use of accessible signals
(other than detectable strips and detectable yellow tiles
just ahead of the pedestrian gates) at rail grade crossings
is the lack of standardization among manufacturers.
E. Risk Management
The absence of consistent approach for managing the
risk at pedestrian-rail grade crossings that could assure
(a) the uniformity and continuity of data collection pro-
grams and administration of related databases on all
such crossings; (b) the analysis of risks at such cross-
ings; (c) the prioritization of crossing upgrades; (d) the
introduction of suitable risk controls; and (e) the assess-
ment of cost effectiveness of such measures.
The five-point program of risk management
(affectionately called the five ‗Es‘—‗Engineering,‘
‗Education,‘ ‗Enforcement,‘ ‗Enabling,‘ and
‗Evaluation‘) to increase safety at pedestrian (and ve-
hicular) rail grade crossings. Note that the first three
‗Es‘ have been key underlying principles of Operation
Lifesaver in the USA. ‗Enabling‘ was added during the
formation in Britain of the National Level Crossing
Safety Group (NLXSG) in 2002, and is concerned with
providing resources, people, and systems to facilitate
progress with improving level crossing safety [24].
‗Evaluation‘ was added more recently, and has become
of particular interest in Europe where attention is being
paid to developing common reporting methods for level
crossings (i.e., types of crossings, numbers, and risk
Ethiopian Society of Mechanical Engineers (ESME) - 39 -
Journal of the 21st Annual Conference May, 2017
grade crossings unless these two types of crossings are
adjacent to each other (e.g., adjacent sidewalks on one
or either side of a rail-highway crossing extending to the
other side of the tracks).
B. Engineering Standards
Based on substantial passenger, commuter, and freight
rail operations are leading the effort to develop guide-
lines and engineering standards for safety improve-
ments. Moreover, it is likely that pedestrian safety at rail
grade crossings will benefit in the longer term by the
increasing consistency in standards for warning devices
and treatments among organizations responsible for this
task. As an example of standards consistency, the defi-
nition of advance preemption in MUTCD looks the
same as the one in AREMA and Institute of Transporta-
tion Engineers (ITE) documents as well as in APTA
standards.
The requirement for extra warning time for pedestrians
and motorists in grade crossings of high-speed rail op-
erations is emerging as an additional issue for safety
upgrades at such crossings. Currently, the typical warn-
ing time at crossings where pedestrians may be present
is between 20 and 30 s for conventional speed trains. In
an environment with 110 mile an hour trains, there
would be a need to provide confirmation signals to the
train crew and the onboard computer that the crossing is
clear likely requiring a warning time of at least 80 s.
The question about how pedestrians will react to such
extended warning times at pedestrian crossings remains
to be determined. This is because currently most of the
warning time is built into the time that the train occupies
the crossing. When high-speed trains begin to operate,
most of the warning time is going to be built into the
time for the train approaching the crossing.
Therefore, there would be an extended warning time
where the crossing remains unoccupied while a high-
speed train cannot even be seen on the horizon. This
situation will require ‗‗reeducation‘‘ of the public, espe-
cially in areas where crossings are very near to each
other.
C. Selection Criteria
Number of criteria are used for the selection of warning
devices for deployment at pedestrian- rail grade cross-
ings including pedestrians collision experience at the
crossing, frequency of inclement weather, pedestrian
volumes and peak flows, train speeds, numbers of
trains, and railroad traffic patterns, surrounding land
uses, sight distance for pedestrians approaching the
measurement), and being able to measure the effective-
ness of programs. Little [24] defined these five ‗Es‘ as
follows:
Enabling: The provision of resources through peo-
ple, procedures, and systems to allow the other ‗Es‘
to be effective.
Education: Increasing public awareness of the dan-
gers of crossings and educating pedestrians, road
vehicle drivers, and other users how to use them cor-
rectly.
Engineering: The protection fitted to level crossings
through lights, horns, barriers, telephones, and signs
together with research into innovative means of in-
creasing safety.
Enforcement: The use of laws to prosecute those
who endanger themselves or others by misuse of
crossings.
Evaluation: The idea as envisaged by the NLXSG is
to encourage organizations to set a baseline before
embarking on new initiatives so that the before and
after can be properly compared.
IV. CONCLUSION
Safety upgrades at dedicated pedestrian crossings are not
prioritized as highly as those at highway-rail grade
crossings unless the two types of crossings are adjacent
to each other (e.g., adjacent sidewalks on one or both
sides of a highway-rail crossing extending to the other
side of the tracks).
2. The vast majority of funding available for safety im-
provements is usually planned for rail-highway cross-
ings; very rarely are these funds scheduled exclu-
sively for dedicated pedestrian grade crossings.
3. States with substantial passenger, commuter, and
freight rail operations are leading the effort to de-
velop guidelines and engineering standards for safety
improvements.
4. Cost estimates and/or actual costs of the warning sys-
tems already installed are not readily available.
5. Strong local advocacy is the most important factor,
other than adequate funding, behind effective educa-
tion, outreach, and enforcement safety campaigns at
pedestrian-rail grade crossings.
6. Education and enforcement campaigns must be sus-
Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) - 40 -
tained over time and place and use a variety of tech-
niques to engage the user community. Campaigns for
commuter and light rail grade crossing safety can be
relatively more effective with the active participation
of the transit agency and a captive local audience ex-
posed to the frequency of transit operations.
7. There is no consistent approach for managing risk at
pedestrian-rail grade crossings that could ensure (1)
the uniformity and continuity of data collection pro-
grams and administration of related databases on all
such crossings; (2) the analysis of risks at such cross-
ings; (3) the prioritization of crossing upgrades; (4)
the introduction of suitable risk controls; and (5) the
assessment of cost effectiveness of such measures.
8. It is likely that pedestrian safety at rail grade crossings
will benefit in the longer term by the increasing con-
sistency in standards for warning devices and treat-
ments among organizations responsible for this task.
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Journal of the 21st Annual Conference May, 2017
Ethiopian Society of Mechanical Engineers (ESME) - 42 -
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Journal of the 21st Annual Conference May, 2017
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አድራሻችን፡- ስልክ ቁጥር 251-116 29 30 06 ፋክስ 251-116 29 34 74 የመ.ሣ.ቁ. 1180
ኢ-ሜይል [email protected] ድረ-ገፅ www.midi.gov.et
“ኢንስቲትዩቱ በ2017 በአፍሪካ ቀዳሚ በዓሇም አቀፍ ተወዳዳሪ የሆነ ቀላል የብረታ ብረት እና ኢንጂነሪንግ ኢንዱስትሪ በመገንባት፣ሇከባድ ኢንዱስትሪ ልማት መሠረት መጣል” በሚል ራዕይ ሇሁሇተኛው ዕድገትና ትራንስፎርሜሽን ዕቅድ ስኬት እየሰራ ይገኛል፡፡
አገራዊ የልማት ራዕይን ዕውን ሇማድረግና የተቋቋመበትን ተልዕኮ ከዳር ሇማድረስ በብረታ ብረት እና ኢንጂነሪንግ ልማት ሇተሰማሩና ሇወደፊትም ሇመሰማራት ውጥን ላላቸው ልማታዊ ባሇሀብቶች ኢንቨስትመንት አቅም፣ የምርትና ምርታማነት አቅምና የግብይት አቅምን በማሳደግ ላይ ትኩረት ያደረገ ተከታታይ ድጋፍ በመስጠት ኢኮኖሚው መዋቅራዊ ሽግግር እየሰራ ነው፡፡
በተሇይም የአዋጭነት ጥናት ማረጋገጫ፣ የቴክኒክና የማማከር አገልግሎት ድጋፍ፣የቴክኖሎጂ ሽግግርና ልማት፣ የፕሮጀክት ጥናትና ትግበራ፣የአቅም ግንባታ ስልጠና፣ የምርቶች የፍተሻ አገልግሎት፣ ውጤታማ የምርምርና የምርት ልማት ሥራ በማከናወን የኢንዱስትሪው ምርትና ምርታማነት እንዲያድግ በመስጠት ላይ ነው፡፡
የብረታ ብረት እና ኢንጂነሪንግ ኢንዱስትሪ ልማት ዘርፍን ሇማሳደግ መንግሥት ተመጣጣኝ የማበረታቻ ሥርዓቶችን ዘርግቶ ተግባራዊ በማድረግ ላይ በመሆኑ ሀብትና ዕውቀቱን አቀናጅቶ ኢንቨስት ሇሚያደረግ ልማታዊ ባሇሀብት ሁለ ሰፊ የኢንቨስትመንት አማራጮች አለ፡፡
በአሁኑ ጊዜም በንዑስ ዘርፉ የአርማታ ብረት አምራች ኩባንያዎች፣ የስቲል ፕሮፋይል ኢንዱስትሪዎች፣ማሽነሪና ኢኩዩፒመንት አምራቾች፣ የአውቶሞቲቭ ኩባንያዎች፣አልሙኒየም ፕሮፋይ፣ የኤሌክትሮኒክስና ኤሌክትሪካል ኩባንያዎችና ሌሎች ኢንጂነሪንግ ምርቶች በኢንቨስትመንቱ ሥራ ላይ ተሰማርተው የሚገኙ ሲሆን ከፍተኛ አቅም ይዘው ንዑስ ዘርፉን ሇመቀላቀል በፕሮጀክት ትግበራ ላይ የሚገኙ ድርጅቶችም በእንቅስቃሴ ላይ ይገኛለ፡፡
ኢንስቲትዩቱ እነዚህን ሇመቀላቀል ፍላጎት ያላቸውን ልማታዊ ባሇሀብቶች ተቀብሎ ሇማስተናገድ ሁሌም ዝግጁ መሆኑን ያረጋግጣል፡፡
የንዑስ ዘርፉ ምርቶች በከፊል
SINTEC ETHIOPIA ( PLC )
Engineering Solutions
Design and Fabrication of
structures and industrial parts.
Erection and commissioning of
plant and plant equipment
Rehabilitation and maintenance:
of plant and plant equipment
Service: Arc, MIG,TIG and power
welding and sheet metal
shearing, bending and rolling
Suppliers of
* Elevators and Escalators
Welding Electrodes
Welding Machines
Cutting & Grinding discs
Vehicle & Industrial Filtration
solutions
Generators
Pumps
(‰. ½w. ½Ð. G.)
Contact Us Tel: 251 11647 87 87/88 P.O.Box 7604 Fax # 251 11 6477883
[email protected] www.sintec.com.et Gurd Shola , Addis Ababa