I'm putting my chips on them using the same word we do in the US: conductors? Or is that the other fella in the train
Oh, and they serve as the engineer's eyes when locomoving in reverse. :-)
Not on any system I've taken in the US. The trains have a special control car on the non-locomotive end of the train, and the engineer switches positions when switching travel directions. There is also the practice of using two or more locomotives, with at least one pair facing opposite directions so the set can be hitched to either side of the train, and dual-cab locomotives that can also be hitched to either side with a forward-facing control deck.