Effects of Independently Rolling Wheels on Flange Climb Derailment

The effects of independently rolling wheels (IRW) on flange climb derailment have been investigated through simulations using Transportation Technology Center, Inc. (TTCI)’s *NUCARS^TM dynamic modeling software. Simulations of single wheelsets and hypothetcal light rail vehicles equipped with IRWs show that flange angle and flange length parameters play an important role in preventing derailments. That role is especially critical for independent rolling wheels due to their lack of self-steering capability. The speed contour concept was proposed for engineers to adopt the flange angle and flange length in a logical way for wheel profile design in new vehicles and wheel profile maintenance. It is also shown that the sensitivity of IRW to flange climb is also very dependent on particular vehicle designs.