"Given the climb they need to make I suspect 'helpers' on the hind end in your neck of the woods is quite common. Another practice that has become quite common these days thanks to PTC (positive train control) combined with micro-processor locomotive controls is DPU (distributed power units), placing a locomotive in the middle of the consist. With todays monster long trains this aides greatly with both startup and braking."
Trains are so cool. I know the longer the train and the tighter the turns is a reason there is power distribution through the train. I'm sure the computer systems model the needs as they hook up and place power and braking as needed.
One of the loudest noises I ever heard was a coupling breaking in a switching yard. Man alive I'd been around LOUD things, but that took the cake. It was about 30 feet away. The other side was lined 24" pipe on flat cars I swear it was louder than a Deep Purple concert I was at. People were actually crying at that one, trying to get off the main floor and into the halls it was so loud at times.. I left, when toilet paper quits working, it's WAY to loud.
That coupling was louder. I think the pipe amplified it.
They use to use the same engine/pumps in switching units as submarines too. WWI / WWII era of thinking. BE prepared. Like liberty ships, production is key.. Have a way to power them is also.
If I remember 1/2 was to power the boat and 1/2 was air compressors. They had a few power units and batteries.. What a wonderful thought. I'll stick with the RR stuff and maybe a tunnel or two... LOL
Thinking Submarine, makes me grab for an O2 bottle.. Trains not so much..