On a visit to Montana in 2003 I stayed at the Izzak Walton Inn in Essex. It is a helper station unlike anything else I've seen. The Eastbound trains headed for the continental divide dont even slow down. The helpers give chase, couple up on the fly and shove. When their services are no longer needed, the engineer pushes a button on the control stand and a servo lifts the pin on the coupler and the brakes are applied. There is a transpponder on the pilot that reads the signal from the FRED and matches brake pipe pressure with the train. Very cool and efficient .