What were the different crafts?

Back in the bad old days there were multiple crafts in the roundhouse, but I'm forgetting what they were. Boilermakers? Machinists? Carpenters? Electricians? Pipe/steam fitters? Can anyone list the multiple crafts in the old days, which often had separate unions, separate agreements, and generally did not work across craft lines (a person in one craft could "time slip" the railroad if somebody in another craft did some of their work). I'm wondering how well this interesting bit of railroad history is documented.

JBWX



Edited 1 time(s). Last edit at 02/03/2016 09:54AM by John West.