Single Axle Running Gear with Nonlinear Axle Guidance Stiffness

Within the Shift2Rail project RUN2Rail, an innovative Metro vehicle with single axle running gear is proposed. In NEXTGEAR, also a Shift2Rail project, the work is continued to achieve a higher technical readiness level. For a 2-axle vehicle with a wheelset distance of 8 m the contradiction between stability and curving performance is imminent, and an active wheelset guidance is considered necessary for networks with many small curve radii. For networks with larger curve radii a passive solution might be enough. A nonlinear axle guidance stiffness that has the potential to improve the curving performance is studied here. The running gear frame is modelled in Abaqus® and structural frame modes are implemented in SIMPACK® together with the other suspension elements. To select the properties of the nonlinear spring, simulations are performed to check stability at demanding conditions at 160 km/h on tangent track as well in a curve with 1000 m radius. These two cases give the high and low guidance stiffness of the nonlinear spring. The results show that a nonlinear wheelset guidance can reduce the wear compared to a linear guidance and be an alternative to active wheelset steering for networks with low numbers of narrow curves.