N Scale Helper Units and DPU's

[tehachapifan]

The de-rating concept I was pondering involved plastic diesel locos, like current Atlas or Kato, which I think would simply involve removing idler(?) gears from truck towers in order to turn axle(s) into unpowered, free-rolling ones. I'm not sure if this is the way others may have have done it. I don't do steam, but it seems like it would be way more complicated to me.

[Cajonpassfan]

I don’t know much about DPU’s, but I do experiment with independently DCC-controlled helpers (pushers) on my transition era Cajon layout. A long, 2.2% continuous grade, some 18” minimum radius curves, 36” climb to Summit. Trains, 24-30 cars. My experience so far: keep it SLOW, per prototype, cars consistently weighed, pusher(s) either derated or incapable of pushing the entire train ahead of themselves. Curiously, no issues with (many) truck-mounted couplers *except* on cars immediately adjacent to engines. Also, I find the longer trains’ slack more forgiving....
Whatever that’s worth,
Otto K.