wheel matching technology (wmt) for … · rail guided for true point-to-wing wheel transfer...

WHEEL MATCHING TECHNOLOGY (WMT) FOR FIXED FROGS AND CROSSOVERS

Harry Skoblenick, M. Sc, P. Eng

Bombardier Transportation - Systems Division

5095 Taylor-Kidd Boulevard Millhaven, Ontario, Canada K7M 6R2

Phone: 613-384-3100 [email protected]

Number of words including figures: 5,921

ABSTRACT Excessive wheel shock loads induced when travelling through worn fixed crossovers (frogs) can reduce the design life of rail vehicles while adding to track maintenance costs. At the same time, shock loads reduce the ride quality and the overall passenger experience by jarring and jerking the vehicle during crossover passage. The issue became particularly evident recently on one metro system where elevated rail impact shocks manifested themselves in an unusually high number of fatigue defects discovered during wayside frog inspections and bogie overhaul programs. To significantly reduce and mitigate the problem, an investigation resulted in the development of a simple and cost-effective frog re-profiling solution, which is currently being implemented as a system-wide retrofit. Wheel Matching Technology (WMT) is a new wayside maintenance solution that addresses the noise/vibration problem in aging fixed frogs and diamond crossovers. Based on simple root cause analysis and application of a precision profiled surface, the WMT solution can potentially restore any crossover transfer into a near impact-free condition. This paper will cover the main features of the technology as well as dynamic test results from several restorations completed on the AirTrain BOMBARDIER INNOVIA ART 200 advanced rapid transit system (1) at the John F. Kennedy International Airport, New York, USA. INTRODUCTION The rolling surface profile on most railway turnouts, and in particular the manganese crossover casting (fixed frog), has been pre-defined for many years. The original frog construction was intended to provide a marginal level of rail support to heavy haul wheel designs. When a transit or heavy haul train passes through the crossover, the height and unique profile of the interface should precisely follow the requirements of the wheel to transfer the loads with little to no discontinuities or vertical disruptions. If the complementary profiles of the ‘point’ or ‘wing’ surfaces are mismatched or worn (Figure 1), wheel passage will be unstable leading to frog damage, rail corrugation wear effects, and premature bogie failure.

Figure 1: Defining point-to-wing wheel transfer surfaces

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Wheel widths and tread profiles are sometimes custom specified to suit a particular manufacturer’s requirements. For example, Bombardier Transportation’s self-steering metro vehicles (2) require wheel tapers greater than 4.2 degrees, versus less than 2.6 degrees for standard AREMA heavy rail profiles. When conventional frog crossovers are supplied and installed without matching the casting profile to the wheel’s requirements, transfer surfaces are unlikely to be continuously supported through the interface. Without matching, rolling discontinuities will result in the wheel dropping (or hitting) at one point during the transfer, imparting high forces and accelerating wear/damage to the track and vehicle’s suspension system. On the AirTrain JFK INNOVIA ART 200 advanced rapid transit system, rail height discontinuities from as little as 3/16” (5mm) have resulted in up to 35 G impacts at 40 mph (60 km/h), which significantly reduced operating life expectancy for track and vehicle components. The most common resolution to the wheel mismatch problem is to provide a nominal level rolling surface relative to Top-of-Rail (TOR) on the supportive frog profile during the standard frog repair process. Welded surfaces are mostly profiled either with the use of hand grinders or by portable grinding platforms. Some ‘guided’ devices are secured directly over the frog casting but only provide limited alignment capabilities for a corrective surface. In addition, repairs are normally only applied over a short distance relative to the complete crossover length. However, after repairing the worn section, the finished product is typically visually inspected and checked with a simple gauge (straight edge) to ensure reworked sections are level, uniform, and without gaps present relative to TOR. Present methods do not typically apply a pre-defined optimum point and raised wing profile to better support the true wheel path and thus load impacts are only reduced, not eliminated, by the restoration process. Wheel Matching Technology was developed from a simple concept whereby a uniquely defined process and wheel matching profiling device (Figure 2) are applied to correct the full casting length and achieve stable surface transfers (+/- 0.2 degree accuracy). The process can be easily re-applied to all crossover types, including originally manufactured conformal frog surfaces.

Figure 2: Precision surface profiling device

Technology and benefits The technology is based on root cause analysis and transferring optimum defined surface profiles into the design of the conventional crossover. WMT provides both economic and environmental benefits:

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Impact-free wheel transitions: Ensuring the wheel point-to-wing or wing-to-point transfers are carried out smoothly along the TOR reference line without loss of contact (Figure 3), thereby producing less wear, noise and vibration;

Reduced rail maintenance: Lower frequency of track repair resulting in less down time. Rail corrugations are often initiated adjacent to areas where instability originates (crossover transitions), so corrugation repair is often reduced with frog repair;

Consistent application: Step-by-step process and guide references that can be easily adapted and applied to any particular type of wheel profile, thus allowing ongoing, consistent results;

Reusable inspection tools and profile templates: Process includes specialty pre-defined profile templates

for use by welders and quality inspectors to ensure the finished product is applied consistently and accurately. The templates can also be employed later by track inspectors to routinely monitor acceptable wear and determine scheduled maintenance in advance;

Built-in ride quality inspection: The current corrective welding, grinding methods and inspections

employed are generally only visual in nature and therefore do not provide ride quality verification of the reworked section. The support wheels on the WMT profiling device are machined to the vehicle’s wheel profile, allowing the device to accurately roll through the reworked area for close examination and confirmation of a quality transfer before leaving the job site;

Versatile: This process can be applied to any new or existing frog casting, including spares stored within

maintenance facilities;

Factory inspection possible: Profile templates can also be applied at the manufacturer’s facility prior to shipment of new factory frogs;

Reduced health hazards: Lower rework frequency reduces inhaled gases from welding manganese castings, which may lead to Alzheimer’s disease; and

Improved track safety resulting from fewer fatigue failures within track and vehicle components.

Figure 3: Custom applied TOR point-to-wing transfer surfaces

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How does the WMT solution work? The WMT technique relies on the preparation and analysis of pre-defined 3D surface contours that are modeled through specialty software. The transfer casting to be investigated and an extruded wheel profile that exactly matches the required axle design (nominal half-worn condition) are modeled (Figure 4). The wheel extrusion (aligned from TOR reference) is then precisely located over the casting profile at various alignment positions to mimic the limits of the wheel path through the crossover. The required surface plane angles (two minimum) are then determined to provide the full-length TOR wheel support requirement.

Figure 4: Extruded wheel profile and 3D frog casting After confirming no loss of wheel contact or elevation change during wheel passage, digital “slices” are defined from the surface profile at specified distance intervals along the casting length. The slices provide the images for fabrication and assembly of a rigid frog inspection template.

Figure 5: Frog inspection template

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WMT - System concept

To apply the customized matching surface profiles as defined for a specific wheel and casting shape, stepped weld bands up to ¼ inch above TOR are first applied, starting at the throat — as defined in the 3D model. The rail-guided profiling device was developed to be field assembled without tools and to automatically roll through the wheel centerline position within the crossover. Once positioned along the rail and magnetically locked, profile angles previously defined for the application are set up and surface planed end-to-end within +/- 0.2 degree accuracy (Figures 6, 7, and 8). Depending on the platform length of the guidance mechanism, one setup position is typically required to shape the full installation.

Figure 6: Frog profiling and guidance platform

Figure 7: Wheel profile path over No.6 frog (3.4 degree taper repair)

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Figure 8: Completed No. 6 frog repair (3.4 degree taper) To validate and inspect the precisely applied transition surfaces, the WMT device has custom wheels and axles with the same profile and wheel tread spacing as the vehicle in order to roll through and simulate wheel contact behaviour over reworked transition sections (including throat and heel) prior to normal train service. Summary of benefits

The profiling device is rail supported and guided to represent the actual wheel passage through the crossover. The main benefits of the technology include:

Light weight and portable for ease of field assembly and placement on track (150lb)

Rail guided for true point-to-wing wheel transfer movement through frog

Rigid end-to-end linear guide providing open view of repair process

Four (4) degrees of precision adjustment provides custom setup when adapting to new applications and installations

Supports portable power unit for rail corrugation removal within turnouts

Elimination of speed restrictions over high impact crossover locations

The profiling process is compatible with any crossover technology regardless of type or manufacturer. Re-profiling can be accomplished over fixed frogs, moveable point crossovers, rail and switch joints, and over standard rail surfaces within repair areas. The concept provides the ability to validate surface profiles and gauge wear rates over the life of the turnout. The profile template together with the stepped calibration tool, are applied to inspect the height of the finished frog surface relative to the bottom of the coloured band — representing the optimum wheel contact position. If the wear gap is greater than a pre-determined step height (for example, the red line in Figure 9), the frog surface profile is scheduled for repair.

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Figure 9: Frog repair inspection with calibration tool The templates are also applied, for greater cost savings, at factory inspections where custom profiled surfaces can be specified and verified before receiving and installation. FIELD TESTING

Since 2010, the WMT process has been evaluated on the 8 mile elevated double-track AirTrain JFK system at JFK International Airport, with revenue service operating speeds reaching over 50 mph (Figure 10). With 42 mainline crossovers (AREMA RBM No. 6 and No. 8) throughout the alignment and scheduled for repair or replacement, WMT has been applied to date at 16 locations while eight other locations have received new replacement one-piece wheel-matched or conformal-type frog castings.

Figure 10: AirTrain JFK mainline alignment

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Since opening in 2004, annual dynamic impact measurements have been recorded with a test vehicle to monitor track and bogie stress performance over the crossovers. Comparing test results, WMT-reworked frogs have provided an approximate 70% reduction in bogie forces, as well as a significant reduction in wayside airborne noise (95 dBA typically reduced to 78 dBA). Before/after repair results at 45mph operating speeds over crossovers H5, H7, H9, and H11 are illustrated in Figure 11.

Figure 11: Comparing bogie strain measurements - before and after Bogie strain measurements on WMT repaired crossovers were also compared to those where new replacement conformal profiles were installed Impact forces over a new one-piece replacement conformal-type manganese frog casting (H9), with installation costs of 35 KUSD, were near identical to the field rework WMT RBM-type frog castings (H5, H7, and H11), with rework costs of less than 3 KUSD. This demonstrates that the WMT device and process can be very cost effective for optimizing in-situ crossover repairs, while also providing reduced operational interruptions.

Figure 12: Comparing bogie strain measurements - WMT vs. conformal frogs How does WMT compare against moveable point crossovers? Transit vehicle manufactures and railway authorities have often specified moveable point crossovers as the preferred choice for newer wayside installations. However, when considering the added design complexity, added interfaces,

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higher maintenance costs and reliability concerns, these systems can add considerably to the capital and true life cycle cost of the installation. To evaluate how the performance of crossovers with the WMT system compare against those with the traditional moveable point configuration, bogie stress tests were conducted at two site locations. The results, illustrated in Figure 13, show that the WMT process provides equivalent or better performance, even at higher operating speeds. Other benefits include the ability of maintenance personnel to precisely apply and maintain the necessary special trackwork profiles thus improving system reliability and lowering operating costs.

Figure 13: Comparing bogie strain measurements - WMT vs. moveable point frog CONCLUSION

Wheel Matched Technology is a new wayside maintenance system for repairing single and double crossovers based on simple root cause analysis. The technology has the ability to restore point-to-wing transfer surfaces to a stable, near impact-free condition as demonstrated in Figure 13. The technology may be seen as an obvious but fresh corrective approach to mitigating historical noise and vibration problems evident in multiple types of conventional crossovers (single and diamond) in service on rail transit and heavy haul installations worldwide. The analytical model approach with specialty equipment and a sound application process have proven to reduce the escalating vehicle and wayside maintenance costs for the AirTrain JFK ART 200 system. The new process is suitable for inspecting and repairing existing track infrastructures and provides an alternative to the more expensive moveable point crossovers. Based on simple and portable devices, setup and inspection tools can be tailored to most system-specific requirements. The provided field testing results, comparative wheel impact cases and costing summaries support the stated benefits.

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Figure 14: Diamond crossover scheduled for WMT repair (Fall 2014) Acknowledgements [1] Bombardier Transportation, JFK System Services, New York, New York, USA [2] Bombardier Transportation, Systems Division, Kingston, Ontario, Canada List of Figures Figure 1 : Defining point-to-wing wheel transfer surfaces Figure 2 : Precision surface profiling device Figure 3 : Custom applied TOR point-to-wing transfer surfaces Figure 4 : Extruded wheel profile and 3D frog casting Figure 5 : Frog inspection template Figure 6 : Frog profiling and guidance platform Figure 7 : Wheel profile path over No.6 frog (3.4 degree taper repair) Figure 8 : Completed No. 6 frog repair (3.4 degree taper) Figure 9 : Frog repair inspection with calibration tool Figure 10 : JFK AirTrain mainline alignment Figure 11 : Comparing bogie strain measurements - before and after Figure 12 : Comparing bogie strain measurements - WMT vs. conformal frogs Figure 13 : Comparing bogie strain measurements - WMT vs. moveable point frog Figure 14 : Diamond crossover scheduled for WMT repair (Fall 2014) * © 2014, Bombardier Inc. or its subsidiaries. All rights reserved.

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© AREMA 2014 11

WMT Frog Renewal Program• Summary

Custom designed Conformal Frogs were used to replace high-impact (worn) 115-lb. RE #6 and #8 RBM Frog casting on JFK AirTrain mainline - 44 frogs over 9 mile - test program compared performance between New conformal replacements with alternative low-cost WMT Renewal process.

Before repair, wheel transfer path across worn ‘Point / Wing’ transfer area p p gmeasured 0.35 - 0.45” below TOR.

After, wheel transfer occurs @TOR height … wheel maintains vertical position and rolling contact point over full length of frog … no lateral or vertical suspension movement … no impacts.

Revenue vehicle test demonstrated suspension strain reduction over 70% …track noise 90dBa reduced to 77dBa (15m)

Repair time: welding + profiling : 3-4hrs (replacement: 3-4hrs)

New Conformal InstallationsCost > 30K $USD

WMT Repair MaintenanceCost < 2K $USD

Presentation will focus on JFK

Renewal Process

Transit railways often specify Moveable Point Frogs for

vehicles requiring low N&V applications … Substitute

Moveable Point with new WMT Fixed Frog for > 400% savings

Cost > 120K $USD

Cost > 30K $USD Cost < 2K $USD

New Conformal 115-lb RE #8 Frog Nortrac WBM Frog

Optimum TOR Wheel SupportPoint-to-Wing

Wing

Point

Matched Wheel Load Transfer at TOR

Wing

Wheel

PointWing

Transfer angle varies with wheel profile

Matched Wheel load transfer at Point-to-Wing

Wheel

PointWing

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Typical RBM Frog at JFK Typical RBM Fixed Frog

Point

Wing

Conventional Wheel Transfer Point-to-Wing

Transfer gap varies with wheel profile and frog design

Wing too low for TOR wheel transfer

Traditional Frog Repair Equipment

Traditional Manual Repair / Inspection

• Performance Test Comparison New vs. Rework

• WMT Frog Profiling Device

• Baseline Design

• Preparation and RepairPreparation and Repair

• Profile Inspection Program

• Adapted for Crossovers +

• Summary

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JFK AirTrain Alignment 9 mile - 44 switches – Service since 2003

45mph

Vehicle Bogie Stress Results Frog Impact Comparisons

Strain Levels after frog modification (150)Strain Levels @ frog without

modification (320)

Bogie Strain Levels on tangent track (80)

NewRepairWorn

Vehicle Bogie Stress Comparisons Before/ After Results (H5, H7, H11 vs. H9)

Conventional Rework

Red Line - Strain Levels before frog modifications

Yellow circle - Strain after frog modifications

Average Strain Levels on non-frog tangent track

Typical Moveable Point Frog (Vancouver Sky Train)

Strain before frog modifications

Strain after frog modifications

Average Strain Levels on tangent track

Bogie Stress Comparisons WMT vs. Moveable Point

Comparison of Strain Range at SG2 between JFK (fixed frogs) and Vancouver (movable frogs)

250300350400450

ange (uE) Strain on Moveable Points

Strain before frog modifications

050

100150200

0 10 20 30 40 50 60

Speed (mph)

Str

ain

Ra

JFK at H5, H7, H9 & H11 - June 2010

Vancouver Millenium Line from Commercial to Columbia stations

JFK at H5, H7, H9 & H11 - Dec 2010

JFK at H5, H7, H9 & H11 - May 2011

Strain after frog modifications

Average Strain Levels on tangent track

• Performance Test Comparison

New vs. Rework

• WMT Frog Profiling Device• Baseline Design

• Preparation and Repair• Preparation and Repair



• Summary

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WMT Frog Profiling Device

Diesel 3-phase 240Vac Generator 200Hz High-Frequency Grinder

+/- 0.2 degree Accuracy Automatic Dual-angle Setup

WMT Frog Profiling Device 4-Axis Fine Adjustment Control

5” Cup Stone 4-Axis Head

Control Tilt and Slide

Full-Length Frog Profiling40” Linear-Slide Motion

WMT Frog Profiling DeviceTrack Center Guidance

WMT Frog Profiling DeviceMagnetic Rail Clamps

WMT Frog Profiling Device Built-in Cup Stone De-glazer

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New vs. Rework


• Baseline Design




• Summary

Defining TOR Profile Angle Wheel Contact Point

Wheel Contact Profile Angle

Defining Frog Profile Angles Wheel Contact and Clearances

Frog Casting

Contact Angle #1

Defining Frog Profile Angles Wheel Contact and Clearance

Clearance Angle #2

Frog Casting

Shifting Wheel Contact Path Diamond Crossover

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New vs. Rework


• Baseline Design

• Preparation and Repair• Preparation and Repair



• Summary

Full Length Weld Build-up Wing 1/4” above TOR

Weld Build-up and Height Checks Weld Build-up at Point and Wing up to 1/4” above TOR

Handling and Protective Equipment

Wing

Profiling Point-to-Wing Transfer

Point

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Full-Length Frog Profiling

Wi

Frog Profile Provides TOR SupportEnd-to-End Wheel Matched Surface

Coverage over full wheel width

Point

Wing

Accurate Profile Inspections Completed WMT Repair

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Profile Transfer - Throat

Wheel Contact Bands @ TOR height -surface overlap provides seamless transfer


New vs. Rework


• Baseline Design




• Summary

Repaired Frog - Surface Finish Developing Rail Hardness Rolled surface vs. Impacts

-

Profile Inspection Template

Wheel Contact Band for TOR height -schedule re-weld when measured gap with frog surface greater than 0.15”

Profile Inspection Template

Point

Wing

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Frog Profile Inspection Wear Data Sheet

Off-site WMT Renewal

Off-Site or Factory Profile Inspections • Performance Test Comparison

New vs. Rework


• Baseline Design



• Adapted for Crossovers +• Summary

Profiling Double Crossovers Profiling Double Crossovers

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Removing Rail Corrugation Special trackwork

Correcting Mis-matched Surfaces Rail Joints

Summary of WMT Program

JFK AirTrain has 44 mainline No. 6 and No. 8 AREAM frogs and 4 double crossovers … 20 frogs profiles corrected to‐date with Repair process plus 12 NewWMT replacements installed … 55mph max operating speed.

100% mainline to be up‐graded by 2015 ‐ predicting significant track repair and vehicle overhaul cost savings over system life.

Conducting 5‐year wear and N&V monitoring program of Repair vs. NewWMT replacement frogs to confirm service life expectancy ‐ after 3 years, near identical (0.06” wear) performance.

Discussions in progress to advance WMT Product and Process into international transit and heavy rail markets.

Patents pending for Process, Equipment, and Inspection Tools

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wheel matching technology (wmt) for … · rail guided for true point-to-wing wheel transfer...

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