System-wide impact of vehicle innovations – Evaluating track-friendliness during vehicle design

The cost of maintenance of railway tracks due to vehicle passage is a major limiting factor to the competitiveness of railway sector in EU. For instance, in Sweden in 2017 only, 2800 million SEK was spent on track maintenance and reinvestment due to wear and tear caused by traffic. Considering this, there is a major incentive to operate track-friendly vehicles that also facilitate economically feasible maintenance strategies. In this context, the NEXTGEAR project aims to incorporate a track-friendliness module in the ‘Universal Cost Model 2.0’ that can estimate operating costs for a given set of operational parameters such as vehicle suspension design, energy usage, track geometry, etc. Such a tool could be useful in estimating the costs for a train operator for a given route and application. However, estimation of costs due to track damage is a complex cross-disciplinary task encompassing varying domains such as vehicle dynamics, tribology, economics, maintenance policy etc so that actual damage in the infrastructure can be linked to maintenance actions and thus costs. Currently there are two major diametrical approaches such as the ‘Bottom-up’ Engineering approach that seeks to create accurate engineering models of vehicle, track, etc. Then there is the ‘Top-down’ Econometric approach that seeks to create statistical models linking the operating variables with historically recorded cost data. Also, track damage itself manifests in various forms such as wear RCF and settlement and it is extremely useful to understand the distribution of costs amongst them. Nowadays a Hybrid approach is being developed that can bridge the limitations of the other two methods. Eventually all these models seek to calculate differential operating costs due to the introduction of vehicle innovations during the design stage, hence contributing to the overall economic feasibility of the railway system.