Train maintenance is relatively simple. But 'planned engineering work' is a regular feature on both the tube and on mainline trains, with train services replaced by a bus so that track maintenance can be done safely.
The situation on mainline rail seems to be that revising the timetable and dealing with signalling issues is too much effort. So it's easier to organise a posession for a stretch of track in both directions.
I'm sure wrong-way working happens occasionally, but it doesn't seem to happen much here.
I know that in Stockholm there is no technical reason for the subways to close after midnight - which they do. They used to run all night (though they did not run often in the middle of the night), but a couple of years ago they decided to stop. It was a mixture of preventing crime, preventing homeless persons to sleep in the subway stations, making maintenance easier and the general urge to look like they were doing something. The night-time bus drivers were not so happy about it. A vote for PES is a vote for EPP! A vote for EPP is a vote for PES! Support the coalition, vote EPP-PES in 2009!
you are the media you consume.