Benefits of mechatronically guided vehicles on railway track switches

Conventional rail vehicles struggle to optimally satisfy the different suspension requirements for various track profiles, such as on a straight track with stochastic irregularities, curved track or switches and crossings, whereas mechatronically guided railway vehicles promise a large advantage over conventional vehicles in terms of reduced wheel–rail wear, improved guidance and opening new possibilities in vehicle architecture. Previous research in this area has looked into guidance and steering using multi-body simulation models of mechatronic rail vehicles of three different mechanical configurations – secondary yaw control, actuated solid-axle wheelset and driven independently rotating wheelsets (DIRW). The DIRW vehicle showed the best performance in terms of reduced wear and minimal flange contact and is therefore chosen in this paper for studying the behaviour of mechatronically guided rail vehicles on conventional switches and crossings. In the work presented here, a mechatronic vehicle with the DIRW configuration is run on moderate and high-speed track switches. The longer term motivation is to perform the switching function from on-board the vehicle as opposed to from the track as is done conventionally. As a first step towards this, the mechatronic vehicle model is compared against a conventional rail vehicle model on two track scenarios – a moderate speed C type switch and a high-speed H switch. A multi-body simulation software is used to produce a high fidelity model of an active rail vehicle with independently rotating wheelsets where each wheel has an integrated ‘wheelmotor’. This work demonstrates the theory that mechatronic rail vehicles could be used on conventional switches and crossings. The results show that the mechatronic vehicle gives a significant reduction in wear, reduced flange contact and improved ride quality on the through routes of both moderate and high-speed switches. On the diverging routes, the controller can be tuned to achieve minimal flange contact and improved ride quality at the expense of higher creep forces and wear.