Abstract: In order to study the dynamic behavior of the light rail vehicle passing through the turnout with small radius, select the typical M+F+T+F+M 5 module train as the research object. The low-floor train gradually develops from the traditional wheelset to the independent wheelset, but there is a big difference between the two steering abilities. The cases of all traditional wheel and all the independently rotating wheels (IRWs) are selected. Establish the low-floor vehicle train model and the turnout model with variable cross-section based on the multi-points contact method and system dynamics method. Taking the China 7th turnout as an example, analyse the dynamic behavior of the different vehicles, and compare the difference between the two cases. The results show that there is more lateral displacement fluctuation and contact point jump compared with the ordinary curve when the train passing through the turnout, and the wheel-rail forces increase rapidly. The all IRWs vehicle has more flange contact and wheel partial wear compared with the all traditional wheels vehicle. Compared with the other vehicles' wheelset, the wheelset lateral force of the leading vehicle is larger, the wheelset of the tail vehicle has more wheel jump, and the wheelset of the middle vehicle is safer.

Key words: dynamics behavior, independently rotating wheels, light rail vehicle, turnout passing