Wheel forces during flange climb. II. NUCARS simulations

The Association of American Railroads (AAR) has used its Track Loading Vehicle (TLV) to undertake a series of controlled flange climb derailment tests. This test program was performed on a section of tangent track at the AAR, Transportation Technology Center (TTC), Pueblo, Colorado, USA, and was the first time that controlled full-scale flange climb derailment testing had been performed in the USA. The primary objective of the project was to re-examine the current flange climb criteria used in the Chapter XI track worthiness tests described in M-1001, AAR´s Manual of Standards and Recommended Practices (Anon, 1993). Another objective was to compare the flange climb conditions obtained in the experiments with predictions made using AAR´s general vehicle dynamics simulation program NUCARS. This paper discusses the comparison of NUCARS predictions and test results for flange climb derailment boundaries. Some measurements and predictions of the distance required for the wheel to climb were also made