The works drawings show that the wheels were designed to be capable of conversion or building to suit Cape Gauge by changing the position of the tyres on the wheel centres. The wheels suit 3′ 6″ gauge with the tyres in the normal position (above the inner rims), or, as built, with the tyres set back by 1 3/16″ on the wheel centres with the face of the tyre 13/16″ below the inner rim to reduce the back to back by 2 3/8″ for the EAR Metre gauge. I have allowed enough material on the castings for either version to be machined.

1:24 is slightly underscale for metre gauge on 45 mm track, for a more exact scale of track use 41.7 mm track (or model at 1:22.2).

Link to Wikipedia page

Link to Bryn Morgan's SAR group:   https://www.facebook.com/groups/225873694237866/ https://www.facebook.com/groups/225873694237866/