Paul, you've got that right -- scale width is .063 and is almost
misbehave on switch frogs. NWSL sells what they call Proto:HO
which has .063 treads
but "RP25" flanges and back-to-back distance. They
also have Proto:87 wheels with
.063 treads but true-scale flanges, and
those will definitely not run through
normal HO switches. NWSL used to make
wheels with .072 treads and "RP25" flanges.
I had those on a car that ran
on a club layout for years, and it never derailed
>Thanks Richard & others, Checked out NWSL and they
seem to have the entire answer, and a small "book" on this wheel subject.
Looks like the first thing to do, to replace your existing .110 wheels to
something with a more narrow tread, is to measure the axle length and axle
>I have read before that tread-width (like true
prototype width) less than .088, won't run well on "standard type" HO track
flange-spacings at frogs, etc.