I was visiting this evening with a friend of mine who apprenticed as a machinist in England working in a locomotive repair shop, and who has quite a bit of experience with the ins and outs of steam locomotives. I mentioned to him the issue that has undergone some discussion here recently, of alignment between cylinders and the centreline of the drivers. He'd never really seen it in practice, but thought it was perceivable that the cylinder vertical position could have a tolerance of +-2" either way. He also mentioned that any offset like that would be absorbed by the cross-head and really have no effect on function.
