Hi ,
On full size engines details of dimensions of wheels varied all over the place in the early days .
Later on the back to back dimension was standardised for British engines at 4 ft 5-5/8 in .
Tyre width though continued to vary from company to company – anything from 5 in to 5-3/4 in on proper railways and almost anything on industrial ones .
Thickness of wheel hub , amount of inset / stand out of hub centre and actual details of axle ends varied from railway to railway and era to era .
Proper railways had flanges nominally 1-1/8 in thick by 1-5/8 in deep but with a complex taper plus curves profile .
Wheel treads were coned slightly primarily to reduce lateral hunting when running at speed and to some extent to ease travel around curves .
There never really was a completely standard set of dimension for wheels in full size and therefore no reason to have one on models .
Regards ,
MikeW