What I think should be sorted is trains just disappearing from departure screens a few minutes after it should have turned up. This lack of suitable information has persisted for too long. It can happen when a train is going to be late due to late arrival, waiting member of train crew etc., at starting point. Sometimes, but not always, in cases such as this an expected delayed time can be manually input but if not, it just disappears. There should be a facility to provide the information to waiting passengers, i.e .instead of just disappearing
say delayed, preferably quoting an estimated timescale or cancelled showing up if that is the case.