Sustainability by optimal material selection
The appropriate rail-laying strategy paves way for a longer lifetime of rails and wheels.
The European Union has committed itself to shifting a high share of passenger and freight traffic on medium-haul routes from road to rail and waterways. This will lead to an increase in rail traffic and freight volumes, and also in travel speeds, which will result in higher system and material stresses on the tracks. As a result, maintenance costs will inevitably rise, and new methods will have to be developed to keep these maintenance costs as low as possible. A comprehen-sive digitization strategy and corresponding develop-ment tools will make it possible in the future to predict the effects of higher loads on the wheel/rail system, and thus to make an optimal material selection for wheel and rail.
R&D methodology rail
modules to cover the entire railway track development chain. These modules range from simulation and wheel/rail model tests to new track laying strategies and maintenance concepts. Computer-aided multi-body simulation (MBS) can be used to determine the stress conditions prevailing in the track in wheel/rail contact, such as at the contact area, contact pressure and von Mises stress. The realistic operating conditions derived from such methods can then be transferred to wheel/rail model tests. To avoid time-consuming and cost-intensive field tests, investigations are carried out on the model test with a focus on damage-relevant parameters for the stress zones using material samples carved out from real wheels and rails.
The wheel/rail tribometer developed at AC²T is equipped with comprehensive online measurement technology and enables, among other things, the experimental simulation of different environmental conditions (temperatures from -20°C to 70°C, air humidity, sand, etc.) and the contact conditions, including those of different curve radii in the railway track. The development of new track laying strategies by the project partner can thus be significantly supported.
The wheel/rail development environment at AC²T complements both the development and validation processes at the project partners, reduces mainten-ance costs and facilitates a systematic selection of wheel and rail materials.
Impacts and effects
The test principle used – in combination with the technical equipment (tribometer) and the procedure – enables the characterization of wheel/rail material combinations for approx. 100,000 passes of the wheel over the rail head, within just three days. This corresponds to a track lifetime of several years. The short duration of the model tests is sufficient to determine essential track-relevant damage parame-ters such as plastic deformation, wear resistance and fatigue with good transferability to real operation. The combined use of FEM simulation and the wheel/rail model test rig allows different new wheel and rail materials to be characterized and evaluated in the shortest possible time regarding the expected lifetime. In addition to railway track systems, the same test principle can also be used for highly loaded crane rail systems.
Project coordination (Story)
DI (FH) DI DI Dr.mont. Andreas Trausmuth
AC2T research GmbH