Interface - The Journal of Wheel/Rail Interaction

124-POUND RAIL

Examining 124-Pound Rail (continued)

The wear levels for all stages of the analyses (shown in Table 2, previous page) were arbitrarily chosen. Comparison of the percentage change in head wear is shown in Table 3.

Loads were applied to the FEA models as shown in Figures 3a, 4a, and 5a (click figures at right to enlarge). A vertical (downward) load of 40 kips and a shearing horizontal force of 20 kips were applied to the center of the running surface of each rail section to simulate low rail conditions. Similarly, a vertical (downward) load of 40 kips was applied to the center of the running surface in combination with a horizontal flange force of 20 kips applied at 0.375 inches below the actual top surface of the head of each rail section to simulate high rail loading conditions. Dynamic and / or impact loading was not simulated in any of these analyses.

Results of FEA
Sample results of the stress analysis are presented in Figures 3, 4 and 5. A stress range of 0 to 90 ksi was arbitrarily chosen for presentation of Von Mises stresses, and an arbitrary range of -90 to +90 ksi was chosen for the individual orthogonal stress tensors. Figure 3 uses the 115-pound rail to show the six orthogonal stress tensors. As can be seen, the longitudinal stresses dominate. Nevertheless, obtaining a better picture of the combined stress effect requires aggregation of all of the stress tensors. The von Mises stress provides one such aggregate. The von Mises stresses are compared for the three rail section in Figures 4 and 5. Again, the 124-pound rail section shows better stress management than the other two rail sections.

Maximum vertical and lateral displacement of the rails with percentage changes are summarized in Table 4. As can be seen, displacement of the 124-pound rail section is about 25% less than that of the 115-pound rail. This is due to the additional strength from the greater head material. The transverse displacement values are even more dramatic, showing reductions of as much as 35% at the maximum wear analyzed.

The track was supported on an elastic foundation by vertical and horizontal springs with stiffness of 1,500 lb/in per unit length of rail track. This simulates track on 21-inch tie spacing with limestone ballast on soft subgrade.

< PREVIOUS PAGE | PAGE 2 OF 3 | NEXT PAGE >