This excellent series, first broadcast in 1988, is on iPlayer now - http://www.bbc.co.uk/iplayer/episode/p011v8dj/The_Train_Now_Departing_The_Long_Drag/ . It's available for the next ten years, so there's time for those you who are ethnically-cleansed from using iPlayer to find a way round it...
It's largely about closures and subsequent preservation.
It's on YouTube, too.
http://www.youtube.com/watch?v=IMk_h6ZqK7U