Introduction to Railroad CapacityModule 2-D

Samuel L. SoginGraduate Research Assistant

University of Illinoisat Urbana-Champaign

Outline

IntroductionFactors of capacityMainline capacityYard capacityNetwork capacitySchedulingEconomicsQuestions

Related Fields to Capacity Research

AnalyticsData miningNetwork optimizationQueuing theoryRegression modelingRisk modelingSimulationUtility models

Railroads’ Capacity History19th and early 20th century: Great expansion of railroadsWorld War I: War traffic brought network to standstill due to insufficient capacity due to inefficient operations, 1920s: Relative balance between capacity and traffic levelsGreat Depression: Loss of traffic led to excess capacityWorld War II: Congestion from war traffic After WWII: Overcapacity as passenger and freight traffic declined1990 - Current: Growth in traffic and market power has permitted railroads to spend substantial amounts to remove choke points

More Demands on U.S. Railroad Network

ReliabilityIntercity Passenger Trains

Commuter Service

Low CostTransportationFreight Growth

Environment

Cambridge Systematics. (2007). National Rail Freight Infrastructure Capacity and Investment Study.

Problems of Capacity Shortages

Inability to handle more trafficDecreasing level of serviceDiminished ability to recover from a disruptionLimited windows for track maintenanceCrew time limitationsIncrease time in yardsIncrease cycle timesAll of these increase costs

Railroads are Capital-Intensive

8 8

Railroads Own Expensive Assets

Track Construction ≈ $2,500,000 to $4,500,000 per mile

171,513 track miles

Locomotives ≈ $1,800,000 each23,732 locomotives

Rail Car ≈ $70,000 each580,635 railroad owned freight cars

Capacity Can Be Measured Anywhere

Transportation Network Railroad Network

DivisionSubdivisionYards & Terminals Industry Facilities

Types of Capacity

Practical Capacity: Ability to move traffic at an “acceptable” level of service

Economic Capacity: The level of traffic at which the costs of additional traffic outweighs the benefits

Engineering Capacity: The maximum amount moved before the system ceases to function

Ultimate Capacity: The system has ceased to function and all signals are red

Kahn, Ata M. Railway Capacity Analysis and Related Methodology. Ottawa, 1979. Print.

What Should “Capacity” Measure?

Utilization

Amount Moved

Reliability

Sogin, Samuel L et al. “Measuring the Impact of Additional Rail Traffic Using Highway & Railroad Metrics.” Proceedings of the 2012 Joint Rail Conference. Philadelphia, 2012.

Railroad Capacity Metrics

Amount Moved Reliability Utilization

Trains

Cars

Tons

Revenue Tons

People

TEUs

(Per Year)

(Per Day)

(Per Hour)

(Per Peak Hour)

Distribution of Arrival Times

Average Delay

Standard Deviation of Delay

On Time Performance

Right Car Right Train

Crew Expirations

Velocity

Dwell time in Terminals

Blocking Time

Signal Wake

Train Miles/Track Mile

Cycle Time

Sogin, Samuel L et al. “Measuring the Impact of Additional Rail Traffic Using Highway & Railroad Metrics.” Proceedings of the 2012 Joint Rail Conference. Philadelphia, 2012.

Important Factors of Railroad Capacity

14 14

Meet and Pass

Single track poses significantly more challenges for capacity

No longer simply limited by train spacing

Must consider “meets” of trains traveling in opposite direction

These impose constraints on schedule

Meets on Single Track

T1

Meets on Single Track

T2

Meets on Single Track

T3

Meet Delay

Passing on Single TrackT

ime

T2

Pass Delay

Track Configuration

Number of tracksSiding lengthSiding spacing (distance & time)Crossover spacing

Single crossoversUniversal crossoversParallel crossovers

Length of bottleneck sectionGradeCurvature

More track can lead to smaller delays

Volume (trains/day)

Del

ay (

ho

urs

)

directional running, DT

bidirectional running, DT

ST, siding every 21.4 miles

Kahn, Ata M. Railway Capacity Analysis and Related Methodology. Ottawa, 1979. Print.

21 21

Two Separate Single Track Lines

High-volume route

Each railroad was operating single track with passing sidings between St. Louis and Texas

Elimination of bi-directional running was one of the big pay-offs in the UP-SP merger

22 22

Directional Running After Merger

• Eliminate “meet delay”

Maintenance FactorsTrack quality

Inspection frequencyTrack failure frequency

Maintenance schedulingLengthFrequency

Surfacing cyclesTie life (Concrete or wood)Rail lifeDynamic defect detection of rolling stock & track

23

Train Types

DynamicsAccelerationBrakingMaximum speedHorsepower to trailing to ratioDistributed power

Cargo CapacityNumber of railcarsNominal capacity of railcarsHeight, width

Influence of HPT on Acceleration Distance

-3.69- -3.08--2.46-

-1.84--1.23-

-0.61-

7,150 ton train

Train Interactions

Number of trains per day or per hourTraffic mixture

Priority differentials: Sacrificing the performance of one train type (freight) to preserve the on time performance of a preferred train type (passenger). Speed differentials: Train that operate at different speeds that can cause passing conflicts

SchedulingDirectional fleeting: Decrease meet delay by only operating in one direction for an interval Type fleeting (time windows): Decrease delays of different trains interacting with each other by separating the traffic type by time of day

Concentration of trains due to the railroad network design

The Impact of Different Type of Trains

Time

Dis

tanc

e

Inte

rmod

al

Am

trak Man

ifest

Unit

Origin

Destination

Time

Signaling

Method of operation (YL, TWC, CTC)Presence of ABS (Automatic block signaling): Allows for closer train spacing and higher speedsSignal spacing: Gives information more frequently on the block occupancySignal aspects: Gives more accurate speed control to following trains allowing for tighter spacingPresence of power switches: Eliminates the need to stop to operate switchesAdvanced control systems

Cab signalingMoving blockPTC

Yards

Length of yard leadsTotal time that yard processes use the mainlineCrew changesSize of receiving and departure yards

Number of tracksLength of tracks

Kahn, Ata M. Railway Capacity Analysis and Related Methodology. Ottawa, 1979. Print.

Options to increase line capacityOperations options:

Increase average speedReduce traffic peakingReduce the variability in speedReduce number of meets & passesIncrease length & weight of trains

Infrastructure options: Line (links):

Add or lengthen passing sidingsAdditional tracks

Junctions (nodes): Add classification tracksExtend yard lines Improve junction designGrade separation

Unlike highways, there is no standard railroad capacity model

The complex nature of railroad operations and limited research funding has prevented a universal capacity model from being developedCurrently several different models are in use

Volume (Trains/Day)

Del

ay (

min

s)

Different Traffic Characteristics will change the Maximum Volume

Acceptable Delay

33 33

Level of Service to measure CapacityHigher delays correspond to a lower level of service (LOS)

Maximum theoretical volumes are never reached to increase level of service of traffic

Metric:Delay

Abril, M., Barber, F., Ingolotti, L., & Salido, M. (2008). An assessment of railway capacity. Transportation Research Part E: Logistics and Transportation Review, 44(5), 774-806.

Railroad Capacity Models

AnalyticalSimplest ModelsCan be computed manually for simple networks

ParametricIdentify critical parametric relationships and focus on the key elements of line capacityEstimates theoretical and practical throughput

SimulationClosest representation of actual operationsData intensive, not practical for network modeling

Computational Intensity Accuracy

Theoretical Low Low-medium

Parametric Medium-high Medium

Simulation Very high Low-high

Theoretical: Maximum Throughput Computation

The maximum traffic flow that a rail line can accommodate under ideal condition

Where: N = Number of trains per day1440 = Number of minutes in a day

Hmin = Minimum headway (minutes)

1440

min

NH

=

Theoretical: Blocking Time Model

Time

Dis

tanc

e

Minimum Head Way

Pachl, Joern, and Thomas White. “Analytical Capacity Management with Blocking Times.” Transportation Research Board: 83rd Annual Meeting (2004)

Theoretical: Single Track Capacity (Poole)

Calculated headway in single track with passes

C = Capacity in trains per day1440 = Number of minutes per 24 hourst = Minutes to travel between sidingst/2 = Average dwell time waiting for opposing train to arrivem = Delay for each meet due to braking, entering the siding, running the length of the siding, leaving the siding and accelerating to full speed2 = number of trains per pair

2

22

1440

mt

tC

Poole, EC. “Costs--A Tool for Railroad Management.” (1962)

Poole Methodology

Siding A Siding B

Time t

Time 0

Time t+m

Time 2t+m+t/2

Time t+m+t/2

Parametric Models

Parametric Model are based off statistical analysis of operating or simulation dataKey infrastructure and operating parameters are identified to predict a delay-volume curveAttributes include

Average speedSpeed ratioPriorityPeaking Siding spacing and uniformityPercent double trackSignal spacing

CN Parametric Model Example

Average Speed 44.38Speed Ratio 1.113Priority 0.342Peaking 1.727

Siding Spacing 7.77Siding Spacing Uniformity 0.49Signal Spacing 0.93

Track Outage 0Slow Orders 0% Dbl Track 75

Maintenance 0

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60

Volume (Trains per Day)

Del

ay (

Min

ute

s)

Average Speed 44.4 mph Speed Ratio 1.113

Priority 0.342 Peaking 1.727

Siding Spacing 7.77 miles Uniformity 0.49

Signal Spacing 0.93 % Double Track 50

Krueger, H. “Parametric Modeling in Rail Capacity Planning.” Proceedings of the 1999 Winter Simulation Conference. Phoenix, 1999. 1194-1200. Web. 21 May 2012.

Railway Simulation Tools

Calculates train movements and makes decisions under the same rules as railroad dispatchers

They account for different equipment types, train consists, train handling characteristics, terrain and track conditions

Common uses of Simulation Tools:Develop operating plansDiagnose bottlenecks and recommend schedule changesEvaluate various capital improvement scenariosAssess the impact of adding new trains to a network

Rail Traffic Controller

Developed by Eric Wilson from Berkeley Simulation SoftwareEmulates a dispatcher controlling train movements across a network based on train priorityIntegrated train performance calculatorInputs: track, signals, trains, and scheduleOutput: delay, average velocity, on time performance

RTC Animation

Yard Models

Logan, P. (2006a). People, Process, and Technology – Unlocking Latent Terminal Capacity.Transportation Research Board 85th Annual Meeting presentation, January 24, 2006.

Yard Models (Simulation)

FlexsimCT. “Flexsim CT intermodal rail yard transfer simulation model.” YouTube, 2010.

Network Models

Capacity planningTrain routingCrew planning

Scheduling

FleetingType: Reduce delays due to different train types operating on the same lineDirection: Reduce delays on single tracks lines by reducing the meet delay

Express schedulingDecrease travel time by bypassing intermediate station and terminalsMinimize conflicts with trains in the same direction

Existing ScheduleTrain # 300 302 304 306 308 314 316 318 320 322 324 326 328 330AM/PM AM AM AM AM AM AM AM AM AM AM AM AM AM AMKenosha – – – – 5:51 6:17 – – 6:53 – – 7:15 – 7:51Winthrop Harbor – – – – 5:59 6:25 – – 7:02 – – 7:23 – 7:59Zion – – – – 6:03 6:30 – – 7:06 – – 7:28 – 8:04Waukegan 4:20 4:58 5:26 5:54 6:13 6:39 – 7:09 7:15 7:20 – 7:37 7:50 8:12North Chicago – 5:01 5:29 5:58 6:16 6:43 – 7:12 – 7:24 – 7:41 7:53 8:15Great Lakes – 5:05 – 6:02 – 6:46 – 7:16 – 7:27 – – 7:58 8:18Lake Bluff 4:28 5:10 5:35 6:06 6:22 6:50 – – 7:24 7:32 – 7:46 – 8:22Lake Forest 4:31 5:13 5:39 6:10 6:26 6:54 – 7:23 – 7:36 – 7:50 – 8:25Fort Sheridan – 5:16 5:43 6:14 6:31 6:59 – – 7:32 7:40 – 7:55 8:07 –Highwood – 5:19 5:46 6:17 6:34 7:02 – – 7:36 7:43 – – 8:10 –Highland Park 4:38 5:22 5:50 6:20 6:37 7:05 – 7:31 – 7:46 7:54 8:01 – 8:33Ravinia – 5:25 5:53 6:23 6:41 7:09 – 7:35 7:41 – – 8:04 8:14 –Ravinia Park – – – – – – – – – – – – – –Braeside – 5:27 5:55 6:25 6:44 7:12 – – 7:43 – 7:57 – 8:17 –Glencoe 4:43 5:30 5:58 6:28 6:47 7:15 – 7:39 – 7:51 8:00 – 8:20 8:39Hubbard Woods – 5:33 6:01 6:31 6:50 7:18 – 7:42 – – 8:03 – 8:23 –Winnetka 4:47 5:36 6:04 6:34 6:53 7:21 7:31 – 7:48 7:56 – – 8:26 8:43Indian Hill – 5:38 6:06 6:36 6:55 7:24 7:33 – – 7:58 8:06 – 8:29 –Kenilworth – 5:40 6:08 6:38 6:57 7:27 7:35 – – 8:00 8:08 – 8:31 8:46Wilmette 4:50 5:42 6:10 6:42 6:59 7:31 7:38 – – 8:03 – 8:14 8:33 8:48Evanston Central Street 4:53 5:45 6:13 6:45 7:02 7:34 7:41 – – 8:07 8:13 8:18 8:35 8:51Evanston Davis Street 4:56 5:49 6:17 6:48 7:06 7:38 7:44 7:51 7:57 8:11 – 8:22 8:38 8:54Evanston Main Street 4:58 5:51 6:19 6:51 – – 7:47 – 8:00 – 8:18 – 8:40 –Rogers Park 5:02 5:54 6:23 6:55 – – 7:50 – 8:03 8:15 8:22 – 8:44 –Ravenswood 5:07 5:59 6:29 7:01 – – 7:55 8:01 8:09 – – 8:31 8:50 –Clybourn 5:13 6:06 6:36 7:07 7:19 7:51 8:02 8:08 8:16 8:25 8:31 8:37 8:56 9:06Ogilvie Transportation Center 5:23 6:15 6:45 7:17 7:30 8:02 8:12 8:18 8:26 8:35 8:41 8:47 9:05 9:15

Sogin, Samuel L, Brennan M Caughron, and Samantha G Chadwick. “Optimizing Skip Stop Service in Passenger Rail Transportation.” Proceedings of the 2012 Joint Rail Conference. Philadelphia, 2012. Print.

Genetic Algorithm ScheduleTrain # 304 306 308 310 312 314 316 318 320 322 324 326 328 330AM/PM AM AM AM AM AM AM AM AM AM AM AM AM AM AMKenosha 6:00 6:05 6:11 6:22 6:31 6:38 6:45 6:53 7:00 7:07 7:14 7:21 7:28 7:36Winthrop Harbor 6:12 6:17 - - 6:43 6:50 6:57 7:05 7:12 7:19 - 7:33 - 7:48Zion 6:16 6:21 6:26 - 6:47 6:54 7:01 7:09 7:16 7:23 7:29 7:37 - 7:52Waukegan 6:25 6:30 6:35 - 6:56 7:03 7:10 7:18 7:25 7:32 7:38 7:46 - 8:01North Chicago - - 6:40 6:48 7:01 - - - - 7:37 - - 7:54 8:06Great Lakes - - 6:45 6:53 - 7:12 - - - - 7:46 - 7:59 -Lake Bluff - - 6:49 - 7:09 7:16 - 7:29 7:36 7:45 7:50 - 8:03 8:14Lake Forest - 6:42 6:52 6:59 7:12 - 7:23 7:32 - 7:48 7:53 7:59 - 8:17Fort Sheridan 6:40 - - - 7:16 7:21 7:27 - 7:42 7:52 - 8:03 8:08 -Highwood 6:42 6:47 - 7:03 - 7:23 - - - - 7:58 - 8:10 -Highland Park - 6:50 6:58 - 7:20 7:26 7:31 7:39 7:46 7:55 8:01 8:06 - 8:23Ravinia 6:46 6:53 - 7:08 - - 7:34 7:42 7:49 - - - 8:15 -Ravinia Park - - - - - - - - - - - - - -Braeside 6:47 6:54 - 7:09 - - 7:35 - - - - - 8:15 8:25Glencoe 6:50 6:56 - - 7:23 - 7:37 7:44 7:51 - 8:05 - 8:18 8:28Hubbard Woods - 6:59 7:03 7:13 - 7:32 - - - - - 8:12 8:21 -Winnetka 6:54 - 7:06 7:16 7:28 - - - - 8:02 - - 8:24 8:32Indian Hill 6:56 - 7:08 7:18 - - - - 7:56 - - 8:15 8:26 -Kenilworth - - - 7:20 - - - 7:49 7:58 8:05 8:10 8:17 - -Wilmette 6:59 7:04 7:11 - 7:31 7:36 - 7:51 - - 8:12 8:19 8:29 8:36Evanston Central Street - - 7:14 7:24 7:34 - 7:45 7:54 - 8:08 8:15 - 8:32 8:39Evanston Davis Street - 7:09 7:17 7:27 - - 7:48 7:57 - 8:11 8:18 8:24 8:35 -Evanston Main Street - - - 7:30 - 7:43 7:51 - 8:05 8:14 - 8:27 - 8:43Rogers Park 7:07 7:13 - 7:33 7:43 7:46 7:54 - 8:08 - 8:23 - - -Ravenswood 7:11 - 7:24 7:37 - 7:50 - - 8:12 - - 8:32 8:42 -Clybourn 7:16 - - 7:42 - 7:55 - 8:08 - 8:23 - - - -Ogilvie Transportation Center 7:24 7:27 7:36 7:50 7:54 8:03 8:08 8:16 8:23 8:31 8:37 8:44 8:54 8:59

Sogin, Samuel L, Brennan M Caughron, and Samantha G Chadwick. “Optimizing Skip Stop Service in Passenger Rail Transportation.” Proceedings of the 2012 Joint Rail Conference. Philadelphia, 2012. Print.

Types of Operations

ScheduledAll train movements are planned and followed preciselyCommuter, inter-city passenger trainsSome freight trains

Hold-For-TrafficWait for the necessary traffic threshold to run a trainGrain, coal and other bulk trains

Hybrid Systems

Economics

Project selection modelsDetermining the cost of congestionDetermining the capacity of a railroad lineBase train equivalenceOther operating metrics

Economics of Railroad Capacity

0 5 10 15 20 25 30 35 4015,000

20,000

25,000

30,000

35,000

40,000

Trains Per Day

($

Th

ou

sa

nd

s)

Marginal Revenue

Marginal Cost

Research Needs

Models that capture yard-mainline interactionPredicting the impact of higher speed passenger and freight trains on the same corridorCreating new theoretical & parametric models

References (1) Abril, M, F Barber, L Ingolotti, and MA Salido. 2008. “An assessment of railway capacity.” Transportation Research Part E: Logistics and Transportation Review 44 (5): 774-806.

S Chultz A Ndreas T Anner, and Ralf Bornd. 2005. “An Auctioning Approach to Railway Slot Allocation An Auctioning Approach to Railway Slot Allocation.” Management 45 (October): 163-197.

Cambridge Systematics. 2007. National Rail Freight Infrastructure Capacity and Investment Study.

Carey, M. 1994. “Stochastic Approximation to the Effects of Headways on Knock-On Delays of Trains.” Transportation Research Part B: Methodological 28 (4): 251-267.

Dingler, Mark, Amanda Koenig, Sam Sogin, and Christopher P L Barkan. 2010. Determining the Causes of Train Delay. In AREMA Annual Conference Proceedings. Orlando.

Dingler, Mark, Yung-Cheng Lai, and Christopher P.L. Barkan. 2009. “Impact of Train Type Heterogeneity on Single-Track Railway Capacity.” Transportation Research Record: Journal of the Transportation Research Board 640 (2117): 41-49.

Gorman, Michael F. 2008. “Statistical Estimation of Railroad Congestion Delay.” Transportation Research Part E.

Harrod, Steven. 2009. “Capacity factors of a mixed speed railway network.” Transportation Research Part E 45 (5): 830-841

Ireland, Phil, Rod Case, John Fallis, and Jason Kuehn. 2003. “Perfecting the Scheduled Railway : Model-Driven Operating Plan Development.” System: 1-28.

Kahn, Ata M. 1979. Railway Capacity Analysis and Related Methodology. Ottawa.

References (2)Krueger, H. 1999. Parametric Modeling in Rail Capacity Planning. In Proceedings of the 1999 Winter Simulation Conference, 1194-1200. Phoenix.

Leilich, Robert H. 1998. Application of Simulation Models in Capacity Constrained Rail Corridors. In Proceedings of the 30th conference on Winter simulation, 1125-1133.

Lu, Quan, Maged Dessouky, and Robert C Leachman. 2004. “Modeling Train Movements Through Complex Rail Networks.” Computer 14 (1): 48-75.

Martland, Carl D, Patrick Little, and Joseph M. Sussman. 1994. “Service Management in the Railroad Industry.” Transportation Research Board.

Mattsson, LG. 2007. “Railway capacity and train delay relationships.” Critical Infrastructure.

Pachl, Joern. 2009. Railway Operation and Control. 2nd ed. Mountlake Terrace: VTD Rail Publishing.

Pachl, Joern, and Thomas White. 2004. “Analytical Capacity Management with Blocking Times.” Transportation Research Board: 83rd Annual Meeting.

Petersen, ER. 1987. “Design of single-track rail line for high-speed trains.” Transportation Research Part A: General 21 (1).

Poole, EC. 1962. “Costs--A Tool for Railroad Management.”

References (3)Preston, John, Graham Wall, Richard Batley, J Nicolás Ibáñez, and Jeremy Shires. 2009. “Impact of Delays on Passenger Train Services.” Transportation Research Record: Journal of the Transportation Research Board (2117): 14-23.

Sogin, Samuel L, Christopher P.L. Barkan, Yung-Cheng Lai, and Mohd Rapik Saat. 2012. Measuring the Impact of Additional Rail Traffic Using Highway & Railroad Metrics. In Proceedings of the 2012 Joint Rail Conference. Philadelphia.

Sogin, Samuel L., Christopher P.L. Barkan, and Mohd Rapik Saat. 2011. Simulating the Effects of Higher Speed Passenger Trains in Single Track Freight Networks. In Proceedings of the 2011 Winter Simulation Conference, 3679-3687. Phoenix

Sogin, Samuel L., Brennan M Caughron, and Samantha G Chadwick. 2012. Optimizing Skip Stop Service in Passenger Rail Transportation. In Proceedings of the 2012 Joint Rail Conference. Philadelphia.

Vromans, Michiel J C M, Rommert Dekker, and Leo G Kroon. 2006. “Reliability and heterogeneity of railway services.” European Journal Of Operational Research 172: 647-665.

White, Thomas. 2006. Examination of Use of Delay as Standard Measurement of Railroad Capacity and Operation. In Transportation Research Board: 85th Annual Meeting. Washington, D.C.

Questions?

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Presentation AuthorSamuel L. SoginGraduate Research AssistantRail Transportation and Engineering CenterCivil & Environmental Engineering DepartmentUniversity of Illinois at Urbana-Champaign1203 Newmark Civil Engineering Lab, B118Urbana, IL 61801(847) 899-2711<ssogin2@illinois.edu>

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