Design of a Two Pack Railway Car Using Adams/Rail and MSC Nastran

Objective
To build a model of a two pack rail car and investigate the following:

• Performance assessment of vehicle on tangential and curving tracks;
• Studies of traction and braking;
• Introduction of  flexible components in Adams/Rail using modal flexibility (via MSC Nastran, DMAP and Adams/Rail);
• Dynamic loading of the car body.

Summary
The two-pack car is a unconventional design that needs effort in Adams/Rail to model its kinematic and dynamic behaviour. The main concern of the design was it's ability to negotiate curves of constant and varying radii at the allowable train speeds. The introduction of the flexible car body (via a finite element model) provides a significant improvement in behaviour, as predicted by Adams/Rail modelling, particularly in the low frequency range. 

It also gives a more realistic loading condition for the car body during operation. The first bending and torsional modes of vibration are shown (above and below respectively) after being read into Adams from a MSC Nastran solution. The Adams/Rail solution determined the response of the two-pack car with articulated bogie using the mechanism, rail track and bogie/wheel contact models built into Adams/Rail. With the actual car flexibility, expressed in modal form from a dynamic analysis solved using MSC Nastran and read into the Adams/Rail model, an accurate model for performance assessment was achieved.