On the study of train–track dynamic interactions caused by rail welds on discrete supported rails

• Study of the influence of rail weld dip on wheel–rail contact dynamics.
• Results show a high influence of the position of the weld relative to the sleeper.
• Impact forces are shown as a result of speed, axle load and unsprung mass variations.

The paper studies the influence of rail weld dip on wheel–rail contact dynamics, with particular reference to freight trains where it is important to increase the operating speed and also the load transported. This has produced a very precise model, albeit simple and cost-effective, which has enabled train–track dynamic interactions over rail welds to be studied to make it possible to quantify the influence on dynamic forces and displacements of the welding geometry, of the position of the weld relative to the sleeper, of the vehicle's speed, and of the axle load and wheelset unsprung mass. It is a vertical model on the spatial domain and is drawn up in a simple fashion from vertical track receptances. For the type of track and vehicle used, the results obtained enable the quantification of increases in wheel–rail contact forces due to the new speed and load conditions.