If one were to make some uncoupled wheels for a trolley to run on the underside of an RSJ, should one make the treads match the taper of the RSJ flange, exceed the taper (run on outside of flange) or be less than that or the RSJ (run towards the centre of the flange)?
I'm thinking that they should run on the outside of the flange for stability, but don't know for sure.
Mark Rand RTFM