Just watched a BBC documentary called 'Engines Must Not Enter The Potato Siding'. It's available on the BBC iPlayer site.
http://www.bbc.co.uk/iplayer/search?q=engines%20must%20not%20enter%20the%20potato%20siding (http://www.bbc.co.uk/iplayer/search?q=engines%20must%20not%20enter%20the%20potato%20siding)
Well worth a watch. First shown in 1969 in the 'Tuesday Documentary' series.
Regards, Allan.....