Integrating on-board authorisation measurements with in-service measurements and risk assessment towards more effective running dynamics approval

In-service wheel-rail contact force measurements are increasingly being performed with both on-board and wayside systems for various purposes, such as identifying problems on single vehicles (overloading and unbalance, wheel flats etc.) and enabling predictive maintenance of components. Such a wealth of measurements can be expected not only to fulfil their original purposes, but also to steadily fill in vehicle-track interaction knowledge gaps if properly exploited - e.g. with a big-data approach. One possible exploitation regards the authorisation to place rolling stock in service from the point of view of running dynamics. This issue is carefully addressed in European legislation and usually requires a significant extent of on-track testing. It is still widely considered a topic where significant cost reductions could be achieved without sacrificing safety, and a possible barrier to innovations such as active primary suspensions and steering. A number of research directions have been addressing this issue, first and foremost the use of virtual methods (Multi-Body Simulation) as a supplement to on-track testing. However, the process defined in the legislation opens the door to other possible improvements. It comprises as a key element “return of experience”, and although still essentially rule-based, is open to risk-based approaches such as that defined in the European Common Safety Method for Risk Assessment (CSM RA). Having developed both on-board and wayside wheel-rail contact force measurement systems, the authors consider that the “return of experience” element may further be specified by taking into account, for a given type of rolling stock, the lateral forces and wheel loads that are increasingly being measured in actual service.