I have a couple of GG1s, a "Bang" and RDC "Buddy"; all run well and are reliable. The G's in particular are heavy, powerful, die cast units that are very fast--you may want to rewire the motors in series or utilize diodes to tame them, or not. You can refer to this previous thread for ideas:
https://ogrforum.ogaugerr.com/...ms-engine-run-slower
I also have several of their freight cars and a set of the halloween "peeps," I like them all and they would be great for the purpose you describe. Be mindful of the pricing, which can be all over the map depending on when and where you find them.