I see now. Does those have diesel generators or just large batteries to power the compressor?>>6831
I like that obsession with RC toys of yours.
It's not like we don't use pusher locomotives or double trains, but pushers are usually used for just a short section of the train's route where the grades imply the use of another loco, so they just… man them. You heard that right, most of the pushers are manned. The rationale here is this: the pusher loco is used only on short section where it is really needed, so it is used with many trains per shift and it is already manned, so synching/desynching it to/from the leading loco would be a waste of time. Furthermore, some of the pushers are attached/detached in the middle of the stretch (usually before/after the limiting grade) or even on the go.
This practice doesn't then confine pusher locomotive to the tail of the train, so there are instances of so-called "pusher in the head" (textbook mutually exclusive paragraphs LOL), so again, even despite the physical contact to the "main" loco, the "pusher" is manned and coordinated by voice over radio or maybe by the auto-driving software.
Like on pic related. The "pusher" here is 1.5 bigger and more powerful than the "main" loco.
Same for some double/joined trains. However
there are areas where double trains or pushers are used for longer distances, this is where fancy Russian ISAVP-RT system comes in, which is not only the radio-control system, but also an auto-driving system which uses the auto-driving software to better coordinate the locomotives and correct the commands in accordance to the profile and other stuff to reduce the risk of breaking the train. For example on the video here >>6797
the second loco is likely unmanned.