Analysis of dynamics of a metro vehicle model with differential wheelsets

The operating conditions of light rail vehicles (trams, metro vehicles) are predominantly different compared with those of passenger or freight trains. The increased number of low-radii curves has a negative effect on wheel–rail interaction. The general design of light rail vehicle running gear is inherited from passenger trains and adapted to different loads. However, conventional solutions of a running gear may not provide smooth low-radius curve negotiation in all circumstances. In addition, a two-point contact is likely to occur, which, in turn, leads to accelerated wear of not only the wheels’ tread but also their flanges. One of the proposals to deal with problems associated with the wheel–rail interaction in tight curves is implementing an automotive solution: a differential gear. The aim of the study is to investigate the dynamic behavior of a metro vehicle model equipped with differentials at each wheelset. The differentials were tested in two main variants: open and with internal friction torque. Internal friction torque value was set, consecutively, up to 2000 Nm. The results have shown that on tight curves a differential may improve rail vehicle wheel–rail interaction.