I can't think of any UK train songs that haven't been mentioned, but I must compliment Spaw on his terrific posting. Maybe you could have a look at this Spaw? It's a link to the men of Lostock Hall, which was the last steam depot in the UK (last service train 4th August 1968)

http://www.lostockhallmpd.org.uk/men.html

The whole site is really good, done by a chap called Alan Castle who photographed steam in the 60s and is still at it!

I know that these locomotives might look a bit Mickey Mouse compared to a Pennsylvania K4s, but the spirit of the enginemen was just the same as Spaw's description of his Dad. Unbelievably, well over a hundred of the old steam men turned up for a reunion recently; some in their 70s and 80s, some from abroad, most for the beer!