Evaluation of the vehicle-cargo and vehicle-trackside clearance of long and big railway freight vehicles
Aliyu Kasimu, Wei Zhou, Hongkai Yan, Yazhao Wang, Chao Shen, Qiang Zhang
Abstract
This research presents verified theoretical tools for evaluating the dynamic clearances of special railway freight cars used to transport out-of-gauge cargos, such as Large Power Transformers (LPTs). A theoretical framework is developed to measure two critical clearances: between the vehicle and the cargo, and between the vehicle and trackside infrastructure (geometric overthrow) under different track curvatures. The theoretical models were validated using a full-scale 330 Degrees of Freedom (DOF) multibody dynamics simulation model and a vision-based in-situ experiment of the real car. Results show strong agreement between the theoretical, simulation, and experimental methods, with all deviations being less than 10 %, except for one case (geometric overthrow at 400 m curve radius), where the deviation between the theoretical and experimental result was 10.5 %. For a curve radius of 400 m, the clearance between the vehicle and cargo deviated from the theoretical model by 1.8 mm in simulation and 2.7 mm in experiment. For the 500 m radius, these deviations were 1.4 mm and 3.3 mm, respectively. These findings confirm that the theoretical model, although simple, is a reliable tool for estimating the allowable cargo dimensions and vehicle lateral offset in tight curves. The developed models will help improve transportation safety by providing a scientific basis for cargo-loading rules in out-of-gauge freight operations and transportation route planning.