Dynamic train/track interaction including state-dependent track properties and flexible vehicle components

An existing state-space based numerical method (see Reference [1]) to simulate vertical dynamic interaction between a rolling train and a railway track has been improved and extended. The modified method allows for non-linear track model properties and flexible vehicle model components. Track model properties are separated into linear contributions corresponding to a non-loaded track configuration and increments which are state-dependent. Linear finite element models represent the train and the track modelled as separate components. Model reduction techniques are employed for computational efficiency. State-dependent track model properties are accounted for by applying counter-acting state-dependent forces to the corresponding nodes of the linear track model. The train/track simulations are carried out in the time-domain. The need for a state-dependent track model is discussed with respect to laboratory and field measurements.