CD Laboratory for Enhanced Braking Behaviour of Railway Vehicles

The low rolling resistance of the steel-steel pairing of wheel and rail makes rail vehicles energy-efficient and environmentally friendly. One disadvantage of this contact is the low transmittable forces. In conjunction with high vehicle masses, this can lead to low maximum acceleration and long braking distances. In emergency situations, brakes are therefore used that work independently of the wheel-rail contact, such as magnetic rail brakes, or devices are added that increase the coefficient of friction between the wheel and rail, such as sanding systems.

This CD Laboratory researches the fundamentals of contact between the magnetic rail brake and the rail, taking into account the sand introduced, possible contamination and wetness. This makes it possible to answer questions about increasing the coefficient of friction by conditioning and cleaning the rail using sand and magnetic rail brakes. These investigations form the basis for improving the global braking behaviour, which is made up of the individual braking systems and their interactions. Furthermore, the fundamentals of the dynamic behaviour of the magnetic rail brake during braking are being researched, taking into account rail junctions such as switches or crossings. These principles form the basis for weight savings and for improving the service life of brakes and rail infrastructure, thus contributing to the reduction of energy and material costs.

The main focus of research is the mathematical modelling of the complex contact between the magnetic rail brake and the rail due to the rail geometry, contamination and variable speed. By simulating this contact, the underlying tribological and electromagnetic effects are investigated and key factors influencing the braking force are identified. Accompanying tests on test benches and on the real vehicle are used to derive corresponding models and validate the findings from the calculations. Building on this, the dynamic behaviour and interactions between friction, electromagnetism and structural dynamics of the magnetic track brake are investigated.

The improved understanding of the underlying physical effects and their impact on braking behaviour should serve as a basis for the development of future magnetic rail brakes and sanding systems and the optimum combination of all braking systems. Technical developments from related areas of application will also be supported due to the fundamental nature of the research carried out.