Effect of Design Variation on Service Stresses in Railroad Wheels

The satisfactory performance of a railroad wheel depends on its ability to withstand not only the repeated stresses imposed on it by normal loads and braking conditions, but also the occasional high stresses that develop under abnormal operating conditions. The continuing trend of present railroad operating practices toward higher wheel loads and speeds has created the need for better design criteria to insure that wheel configurations are the best attainable. Under sponsorship of the American Iron and Steel Institute, the General Electric Company developed computer programs to simulate service braking and loading conditions. These were reported at the 1965 ASME Winter Annual Meeting. Now the programs have been applied to different wheel designs and the braking and loading stresses computed. The results indicate that cyclic stresses of significant magnitude may occur under different operating conditions, so fatigue concepts are important in wheel design considerations. There was no one optimum wheel design for all possible service conditions, although several configurations showed promise. A method was proposed for optimizing design for specific service conditions to safeguard against fatigue damage. To fully utilize this technique for design optimization, accurate data relating to service conditions are needed.