Workmen

Workmen

are the backbone to the not train part of the railway. They are plentiful, and ready to assist in work.They usually dress in a blue coat with white shirt and black tie, over which overalls are worn (brown or orange) and a cap common in railworking.

Possible Goof
In theory what the workmen wear would be considered not safe by modern standards. For example no hardhats, no safety vests, eye protection. Since years are never said theirs no diffident error, though there a good chance of it. The possible reason for it being correct, is that the TV series (where workmen are seen frequently) is set before 1970s.