In message , Neil Williams
writes
Interesting - it's also a National Rail thing - apparently, long
possessions allow a lot more work to be done a lot more cheaply than
the same time's worth of overnighters.

Sorry to look at it from the negative view point. But maybe National
Rail and London Underground are just being ripped off by their
contractors.
Just out of interest how does maintenance work take place in other parts
of the world? Do the other major cities/ Western countries have the same
approach to maintenance as we do in this country?
--
CJG