Experimental modelling of lipping in insulated rail joints and investigation of rail head material improvements

An insulated rail joint is a component used to join two abutting rails whilst keeping them electrically separated from one another. This allows for the construction of track circuits and train detection within signalling systems. Electrical failure of the joints can be caused by plastic flow of the rail steel over the insulating gap, known as lipping. In the following paper this failure mode has been experimentally modelled using twin disc testing and indicative conclusions have been formed. It has been found in this testing that endpost thickness does not have an effect on the rate of lipping, but the endpost and rail material do. An endpost with higher compressive strength will perform better while tougher / harder rail steel will also improve performance. The application of a laser clad layer of tougher material on the running surface, however, gave the greatest resistance to lipping.