I'm curious about your solutions to the lego train wheel situation

So I recently submitted a build for BDP, and it raised a few questions on possible solutions for wheels on smaller trains or trains that need to be lower to the ground, my solution was the disk and tile 'wheel' above the real ones as a facade, but I'm curious what do you use for your MOCs that are actually legal building techniques? What I'm designing needs to be as low as possible, since irl the height of these trains are 2.6m only, you almost get in on rail level, and for the proportions to...