Let’s say we have two trains which are identical in all respects other than one has three locomotives on the front and the other has its locomtives distributed…one on the front…one in the middle, and one on the tail end…from an operator’s perspective would the trains handle much differently?
Also, do all units respond the same way to the engineer’s throttle or can each locomotive be controlled independently as required? I ask this because a train may be traversing rolling countryside…the front may be going down a 1% grade while the miiddle is going up hill and the tail end is negotiating a sharp curve…
Can I add another question to that?
Do engineers need to be qualified/trained specially to run DPU equipped trains? If so-is that training basically “seat” time?
I recently retired from Canadian Pacific railroad. Because the power is evenly distributed the you have very little slack or buff forces so train handling is a lot easy especially on start ups and braking especially on 25000 ton potash trains. The run outs or buff forces are greatly reduced on the long 10000 foot trains. The train feels more solid for lack of a better word. When you setup or release the brake each remote gets a radio signal and applies or releases the brakes too in your train. The train responds quicker when braking and the brakes releases faster. Recharging the brake system is faster because each remote aides. Compared to a conventional train that must rely on sending the brake pipe signal just from the head end to the tail through the train line.
To qualify running a DPU was simply having someone ride a couple of trips with you who was already was qualified. There is not too much complicated about the system but at times there can be issues. Generally its just part of the process when you are taking student trips learning to become a engineer.
Originally the electronics were in a dedicated car, called a " robot car" hooked to the mid remote but pretty well all locomotives are DPU equipped. Robot, slave, or remote all refer to the same thing.
You can independently control each unit or have them all do the same as your response. Very rarely would you bother controlling each individual remote. I am only speaking on prairie railroad experience bu not sure if this holds true for mountain railroading. I know it seems weird when you see part of your train is going up hill and part of it down hill but it seems to even out and does not cause issues.
TRAINS magazine had a very good, in depth article in their September (IIRC) issue that went into detail about DPU operations including track dynamics. It’s worth tracking down and reading…