At one time, BNSF tried to establish a process where the Engineer on the leading consist would tell the Engineer on the manned helper to increase or decrease throttle, sort of like verbal Locotrol. Made me want to be physically sick. I worked a lot of trains on Cajon Pass on the head end, mid-train, and cut in ahead of the Caboose. Same on the undulating Fourth District and 2.2% Miramar Hill. Never was radio used.
Common sense, though, now that's another matter. If the ammeter on your engine is in the red, then you might want to ask the Engineer on the other consist whether he is in the same position. Sometimes you have to double the hill. If your engine is having a lot of slipping, you reduce one notch.
