Modern software packages on multibody dynamics can be used as an essential part in investigating train crashworthiness. The parametric studies on the crashworthiness of a typical Australian passenger train have been conducted using the three-dimensional models of a single vehicle car and multiple cars, which were formulated using multi-body dynamics approaches. The results showed that for the higher crash speeds, the crush length or crush force or both of the crush elements in the high energy (HE) and low energy (LE) crush zones should be increased. The simulations on multiple vehicles (up to 10 vehicles) showed that the number of vehicles significantly affects the design of HE and LE crush zones. At the crash speed of 35 km/h, the energy absorbed by the HE is almost consistent for trains with more than 4 cars. The contribution of the number of vehicles to the frontal crash forces can be identified through the simulations. Meanwhile, the effect of train mass to the design of both crush zones, and the effect of design of the crush zones to the wheel-rail contacts are simulated and investigated.