Experimental Setup of an Innovative Multi-Axle Roller Rig for the Investigation of the Adhesion Recovery Phenomenon

Proper values of the adhesion coefficient are the key to guarantee good operations of railway transportation systems in terms of safety, performances and punctuality during both braking and traction manoeuvres. Adhesion can drop to very low values due to contaminants lying on the track. However, the leading wheelsets have a cleaning effect on the rail, so that adhesion recovery can be observed on the following axles. A good knowledge of adhesion and adhesion recovery phenomenon is thus fundamental to optimize the dynamic behaviour of railway vehicles and to develop new algorithms for wheel slide protection (WSP) and antiskid systems. Several laboratory facilities are used to investigate adhesion, due to the high costs of on-track tests with full vehicles. Anyway, these devices do not allow a good simulation of the vehicle dynamics and of the real contact conditions. To overcome these issues, roller rigs usually represent a good compromise in terms of costs, safety, repeatability of the tests and simulation of the real contact conditions and vehicle dynamics. However, typical roller rigs consist of one or more wheelsets rolling over separate pair of rollers. An evolution of roller rigs, consisting of multiple wheelsets acting on the same contaminated surfaces, is thus needed to study the adhesion recovery phenomenon more properly. The paper concerns the experimental setup of an innovative 1:5 scaled multi-axle roller rig developed at Politecnico di Torino. The rig is intended to allow researchers to obtain a deep understanding of the mutual interaction of different following wheelsets running on a contaminated track.