In case you ever wondered.... Yes, it is prototypical to operate a UP engine in reverse on the mainline. I caught this UP unit running in reverse east of Baker City, Oregon, in 1984 (October 13th, I think). It was probably a local detailed to MOW work, but it still counts as prototypical! I guess I should explain that I am referring to "long nose" forward as "reverse". The engine was moving uphill to the left in the picture. The smoke from the engine makes it look like it was pushing the caboose to the right, but that was not the case. There was a strong tail wind blowing from the rear and the train was not moving as fast as the wind.