Marky, people dismiss leaves on the line as a daft excuse but trust me on this one, the person who finds a cure would become immensely wealthy. I'm not saying that maintainers and TOCs don't trot out that excuse glibly to cover other failings but the three main problems it causes are poor rail head adhesion, loss of train detection in track circuited areas & wheel flats which then go on to wreck the rails.
SS1882, don't believe the hype about other countries running a 24 hour railway, maintenance has to be carried out as some time so if the trains are running on all lines 24/7 then important maintenance isn't taking place.
All the gripes are true, just thought I'd give a bit of background info.