There was talk of having co-engineers at one point. This was makes sense on long ID runs.
When I worked there, there were some brakemen who were older, but not too far ahead of me, on the roster. These guys never took promotion to conductor. When the reduced crew agreements came, the had nowhere to go. They were forced to qualify. They had been brakemen on choice jobs, now junior conductors, at the bottom of the extra board.
It is foolish to let progress pass you by. This is why I was willing to go to another terminal, if I could get into engineer school sooner. It's all about getting your name on that roster first.