Dynamic response of a locomotive with AC electric drives to changes in friction conditions

Locomotive traction control behaviour and its dynamic impacts on rails and vehicles have not been comprehensively investigated in respect to transient conditions. Such transient traction behaviour could be more significant than steady state behaviour in determining dynamic traction performance and track degradation (i.e. squat/corrugation formation, etc.). In order to study this effect, detailed numerical simulations are performed to investigate a locomotive's dynamic response to a change in contact conditions. In particular, creep response, vibration of the locomotive, and dynamic normal and traction forces are determined using a developed full-scale dynamics model of a locomotive. The model includes a detailed representation of the AC motor dynamics, which has not been considered in previous works. The results show that the detailed model is capable of simulating the dynamic fluctuations in creep and traction forces that are not considered in simpler models. Such transient responses may cause damage to the track and vehicle components.