My 1st 2 engines were Locosounds, a 2-8-0 and a RS3. The RS3 diesel sound was good, the 2-8-0 sound like a box-o-rocks. I converted both to PS2 then to BPRC. I actually have two RK 2-8-0, the oldest one (the Locosound engine) is a fine, slow puller, the newer one takes a bit more throttle to get moving but I feel it'll end up like the 1st once it wears in/out.
All the heavy diecast engines I have are great pullers, even the RK Imperial USRA 0-6-0.
Another fine puller is my Lionel 4-8-2 and has excellent slow speed under BPRC.
About the only engine I have that isn't heavy is the Weaver RS3, but I never pull more than a few cars with it, I've never tested it to see how many it can pull.
