Development of a contactless sensor system to support rail track geometry on-board monitoring

This paper is focused on the ongoing research, within a work package of the Shift2Rail project Assets4Rail, related to the development of an on-board contactless sensor system able to measure the wheel's transversal position in relation to the rail in order to support track geometry measurements. In particular, this research work focuses on developing a sensor system to support track geometry monitoring performed by the master system under development in other Shift2Rail projects. The aim is to develop a sensor system to detect the relative transversal position between the wheelset and the rail, suitable for the use on commercial (in-service) vehicles. In fact, a possible track geometry monitoring system alternative to the sophisticated and expensive optical/inertial systems and suitable for use on commercial vehicles, could be based on the measurement of accelerations. However, some parameters of the track geometry, such as lateral alignment, are extremely difficult to determine through the measurement of accelerations. In this case, it is necessary to find an innovative sensor system able to determine the wheel's transversal position in relation to the rail. For this reason, this project intends to focus on innovative systems that allow the detection of the wheel-track position by avoiding the optical/inertial systems already used on diagnostic trains. After a state-of-the-art overview on the potentially applicable technologies for the sensor system to be developed, a corresponding analytical tool for comparison of contactless sensors to choose the most suitable technology has been developed and two candidate technologies (stereo and thermal cameras) have been selected and assessed by means of a test platform in the facilities laboratory of VGTU (Vilnius Tech). This work will be the basis for developing a concept design of the sensor system together with a montage solution, which will be finally tested on a vehicle in real operation conditions.