Ian - It's nothing to do with that, and that kind of behaviour would show up on an OTDR download anyway, which all mainline certified traction has to be fitted with.
In this case, the driver failed to cancel the automatic warning system in time after a warning was received for a temporary speed restriction. When they noticed the brakes applying, the fireman isolated the system, which resulted in the brakes releasing. In the interim, the train had passed a yellow cautionary aspect, which the driver had not registered, probably due to distraction, so made no attempt to slow the train. When he noticed the red signal ahead, the brake was fully applied, but far too late to stop, and the performance of the brake wasn't particularly great either, so the train came to a stand over a mainline junction, having missed a side on collision with a high speed express by about a minute.