Track-Related Research, Volume 7: Guidelines for Guard/Restraining Rail Installation (2010) / Chapter Skim
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Pages 12-23
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From page 12... ...
The L/V ratio and flange climb distance criteria proposed in the previous TCRP project (2) were applied to the simulation results.
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From page 13... ...
. Based on these criteria, for the Type 1 transit rail car with a 63° flange angle running on yard track with Level 3 perturbation, the guard rail should be installed on curves with radii less than 3,000 ft to prevent flange climb derailment because the L/V ratios with a 3-ft window (for curves with radii less than or equal to 755 ft)
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From page 14... ...
0 0.2 0.4 0.6 0.8 1 1.2 0.3 0.50.4 0.6 Friction Coefficient Le ad A xl e Hi gh R ai l W he el L /V R=100 ft R=250 ft R=320 ft R=500 ft R=755 ft R=955 ft R=1145 ft Nadal -- 63° Figure 22. Wheel L/V ratio of a Type 1 transit rail car with steady-state curving 15 mph, no guard rail.
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From page 15... ...
0 0.2 0.4 0.6 0.8 1 1.2 0.3 0.50.4 0.6 Friction Coefficient Le ad A xl e Hi gh R ai l W he el L /V R=100 ft R=250 ft R=320 ft R=500 ft R=755 ft R=955 ft R=1145 ft Nadal -- 63° Figure 24. Wheel L/V ratio, Type 1 transit rail car, Level 3 perturbations 15 mph, no guard rail.
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From page 16... ...
Under such conditions, no guard rails are needed for curves with radii larger than 500 ft for the Type 1 transit rail car. Another way to decrease the flange climb derailment risk is to decrease the W/R friction coefficient.
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From page 17... ...
R=100 ft R=250 ft R=320 ft R=500 ft R=755 ft R=955 ft R=1145 ft 0 0.2 0.4 0.6 0.8 1 1.2 0.3 0.50.4 0.6 Friction Coefficient Le ad A xl e Hi gh R ai l W he el L /V Figure 28. The wheel L/V ratio, Type 1 transit rail car, perturbation Level 1, 15 mph, worn rail.
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From page 18... ...
The following conclusions for the Type 1 transit rail car can be drawn from the above analyses: • The flange climb derailment risk is very high for the Type 1 transit rail car with a 63° flange angle wheel. Guard/ restraining rails should be installed on the following: – Yard curves with radii less than 755 ft; the speed limit is 15 mph under Level 2 perturbations.
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From page 19... ...
19 0 0.2 0.4 0.6 0.8 1 1.8 1.6 1.4 1.2 0.3 0.50.4 0.6 Friction Coefficient Le ad A xl e Hi gh R ai l W he el L /V R=100 ft R=250 ft R=320 ft R=500 ft R=755 ft R=955 ft R=1145 ft Nadal -- 75° Figure 32. Wheel L/V ratio, Type 1 transit rail car, 15 mph, 75° flange angle, perturbation Level 3.
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From page 20... ...
0 0.2 0.4 0.6 0.8 1 1.8 1.6 1.4 1.2 0.3 0.50.4 0.6 Friction Coefficient Le ad A xl e Hi gh R ai l W he el L /V R=100 ft R=250 ft R=320 ft R=500 ft R=755 ft R=955 ft R=1145 ft Nadal -- 75° Figure 35. Wheel L/V ratio, Type 1 light rail vehicle, Level 3 perturbations, 15 mph.
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From page 21... ...
These two types of light rail vehicles behave differently, not only on low-speed curving, but also on high-speed curving. Figure 39 shows that the IRW L/V ratios generally increase with the running speed and result in flange climb derailment on 21 0 0.2 0.4 0.6 0.8 1 1.8 1.6 1.4 1.2 0.3 0.50.4 0.6 Friction Coefficient Le ad A xl e Hi gh R ai l W he el L /V R=100 ft R=250 ft R=320 ft R=500 ft R=755 ft R=955 ft R=1145 ft Nadal -- 75° Figure 37.
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From page 22... ...
cant deficiency speed on curves with radii larger than 100 ft and Level 1 perturbations. 4.4 Summary of Flange Climb Derailment Simulations Dynamic curving simulations of the four types of transit rail cars and light rail vehicles with three different flange angle wheels (IRW for Type 2 light rail vehicles only)
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From page 23... ...
• From a safety point of view, the guard rail installation guidelines for the simulated two types of transit rail cars and two types of light rail vehicles (defined in Table 2 in the report) with recommended 75° flange angle wheels are listed below: – For yard curves (15 mph speed limit)
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