Youtube video about building railway infrastructure in England in the 1950s. Some nice footage of tractors and boxes in the first half. https://www.youtube.com/watch?v=zBwoNa7mxY8
Interesting video Cmark. Looks like the HD21 Allis Chalmers was very popular over there. I think the ones shown had the GM 6-110 engine judging by the dual air cleaners on the right hand side. And there was quite the interesting mix of pull scrapers to go with them.