RE: Roundhouse Bill's post ... " "I found by bending the ladders slightly the problem was resolved without any major effort."
Agree ... the engine makes it around most of my R20 90* curves just fine, but the truck bumps into the ladder on a couple of my curves that are likely 'R19' due to irregularities in the old Gilbert curve piece(s) at that location on the layout. So, I'll take a pair of needle nose pliers and tweek the ladder outboard just a bit at the front edge. I believe I can get enough wiggle room with that approach. Looks like the ladder is thin metal vice plastic so it'll take a small bend ok.
Tom