Probably the only full spec RP-25 ex Tri-Orrible wheels in the world.........? :
No running test yet (later) - but we'll now see if tyre coning makes any difference. My hunch is it can't make things can't worse.
The reason I left the flange depth slightly oversize was to leave 'some meat' on the flanges when it came to machining the flange edge radii, R2 & R3 in above RP-25 diagram. Turning 0.018" radii is not really tooled up for 'out the drawer' in the SWW machine shop.
Thanks again to Helmut & Si. (any idea if them thar KD wheels are available in the Y.U.K. ?).
Thanks James, but as Helmut explained, I am working in 48:1 but using HO track standards (poor man's option but I have plenty else to waste my dosh £ on. I also have my local barman & his family to support). So pure HO stuff is way too small for U.S. 'O' Gauge.
Which is all true for the prototype, but not for the "tramway" radii used on model layouts. As even the NMRA state in their RP25, tread taper is not necessary for models, whereas proper fillet and flange rounding are. The 'guiding' effect seen on a single truck or car rolling down a straight length of track is due to the fillet, not the taper. Once it is part of a group of cars being drawn along, all guiding work relies on the flanges, especially in curves.