Center Truck Performance on Low-Floor Light Rail Vehicles (2006) / Chapter Skim
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Pages 23-34
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From page 23... ...
The flange climbing derailment risk of IRWs will be slightly higher than for conventional wheelsets because of the increased lateral forces, the possibility of a higher angle of attack generated by IRWs, and the configuration of LFLRV being studied. Trucks with IRW center trucks are, therefore, fundamentally more susceptible to derailment and, as a result, their behavior can be strongly influenced by other factors, which would normally be of only secondary importance for trucks with solid axles.
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From page 24... ...
Minimal effect Minimal effect Minimal effect No effect No effect Smaller wheel diameter/ wheel flange length Avoidable effect Increases Increases Increases No effect Variation in wheel diameter Minimal effect Minimal effect Minimal effect No effect Minimal effect Wheel parallelism Effects Effects Minimal effect Minimal effect No effect Wheel profile parameters Flange angle Effects Effects Minimal effect Minimal effect No effect Toe radius Effects No effect No effect No effect No effect Flange height Extra safety No effect No effect No effect No effect Tread width Avoidable effect Minimal effect Minimal effect Minimal effect No effect Blend radius Effects No effect No effect No effect No effect Flange thickness Indirect effect No effect No effect No effect No effect Tread radius/taper Effect Effect Effect Effect Effect Other vehicle features Center section fixing to truck Possibly minimal effect Possibly minimal effect Possibly minimal effect No effect No effect Position of secondary suspension Minimal effect No effect No effect No effect No effect Inter-body damping Effect Improves Improves Improves Improves Primary suspension stiffness Effect No effect No effect No effect Effect Use of flange tip running Reduces risk Effect Effect Effect No effect Lubrication Minimal effect Effect Effect Effect No effect Track parameters Gauge tolerances Effect Effect Effect Effect Effect Flangeway clearance Effect Effect Effect Effect No effect Other track features Use of tighter tangent track Effect Effect Effect Effect Effect Sharp curves Possibly Impact Impact Impact Possibly Gauge widening on curves Possibly Impact Impact Impact Possibly Tangent track between curves Possibly Possibly Possibly No effect No effect Use of restraining rail Effect Effect Effect Effect No effect Undercut switches Effect No effect Local effect Local effect Local effect Extra guard rails and house tops Extra safety No effect No effect No effect No effect Embedding rails No effect No effect No effect Effect No effect Flexible switches Effect No effect No effect No effect No effect Switch rail tip design Effect No effect No effect No effect No effect Table 3-1. Summary of measures.
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From page 25... ...
. The Newark Subway has had higher wheel wear on the center trucks of its LFLRV fleet than on the wheels of the motor trucks and has very high rail wear on sharp curves (Section 2.3.3)
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From page 26... ...
The track quality needs to be high in terms of gauge and other variations. 3.6 Contributing Factors 3.6.1 Vehicle Parameters Truck Wheelbase The main effect of varying the center truck wheelbase would be to increase the critical angle of attack on very sharp curves.
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From page 27... ...
• Steep flange angles are better for resisting flange climbing derailments. Shallower flange angles increase the risk of flange climbing derailment caused by the reduced lateral force needed to climb and by reducing the climb out distance once the critical L/V limit is exceeded.
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From page 28... ...
for the following reasons: • Many large-angle crossings requiring flange running -- the outer part of the wheel tread is not used because of the 28 Flange height System Type of car inches mm MBTA 8 Portland MAX NJT San Jose, Santa Clara VTA Houston/San Diego Type 8 Siemens/Duewag Kinki-Sharyo Kinki-Sharyo/Alstom Siemens Avanto S70 0.75 1.063 0.75 (1)
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From page 29... ...
135 (5.51) 140 San Jose, Santa Clara VTA Kinki Sharyo/ALSTOM Houston/San Diego Siemens Avanto S70 Table 3-4.
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From page 30... ...
Primary Suspension Stiffness IRW cars require better resistance to wheel unloading on twisted track than non-IRW cars, because IRW cars generate higher lateral loads. Therefore, vertical wheel unloading must be minimized in order to avoid a risk of derailment.
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From page 31... ...
31 Lubrication system Problems experienced System Track mounted Vehicle mounted Excessive wheel wear Excessive track wear Excessive external noise Excessive internal noise Newark City Subway Yes Yes Yes No Portland Yes Yes No Santa Clara Yes Yes No San Diego Yes Houston Yes Yes No Yes Boston Yes No No No No No No No No No No No No No No Yes Testing Yes Yes No Yes Mitigating System Grease applicators Top friction modifiers Side friction modifiers Wheel wear Track wear Noise Newark City Subway Yard turnouts On Penn Stn. Loop tracks Sharp curves No Yes Yes Sharp curves, Girder rail, embedded track Yes Yes Yes Portland Sharp curves, ballasted track Yes Yes Yes Santa Clara Sharp curves No No Yes San Diego Sharp curves Existing lubrication, no problems with LFLRV as yet Houston Sharp curves Yes Yes Yes Boston Sharp curves No No Yes Table 3-6.
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From page 32... ...
. IRW cars generate higher levels of lateral force and higher angles of attack, which increase wear rates and the risk of derailment.
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From page 33... ...
Lead axle of center truck derailed on yard switch Santa Clara Kinki Sharyo/ALSTOM 2004. Both axles of center truck derailed on switch at 5 mph.
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From page 34... ...
Certain wear patterns will cause the rail profile to change. If the profile is not checked and corrected regularly, this will cause issues.
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