Semi-scale wheelsets

Model Railroader General Discussion (Model Railroader)
1

Hi all,

In Ho scale probably as well as others

What is semi-scale when it comes to wheelsets, Intermountain has them, and the only difference I see is a smaller wheel flange.

Can anyone chime in and let me know.

Thanks

2

In HO scale, a standard HO scale wheel is 0.110 inches wide or code 110. See NMRA S-4.2.

True scale wheelsets in HO scale are 0.064 inches wide or code 064. See NMRA S-4.1.

Semi-scale or code 088 wheels are 0.088 inches wide and are a compromise between standard HO scale and true scale. The idea is Code 088 wheelsets will still work on track that is built carefully to standard NMRA tolerances.

3

The wheel treads are narrower – regular HO scale wheelset wheels are unrealistically wide to allow for imperfections in track gauge. If you don’t have absolutely perfect trackwork you might have problems with semi-scale wheelsets derailing in some of the cheaper brands of turnouts such as Atlas Snap Switches.

4

OK, that makes sense. they are truer to scale, just like #58 Kadee knuckle couplers are truer than #5’s.

HO of course

Thanks