The CSME is trying to minimise the degradation of the aluminium rail and would like the wheel profiles of all 7.25"G and 5"G locomotives and especially driving/riding cars (as these possibly carry the most weight) to conform to the following standards.

The ground level railway turnouts are built to the standard defined in the 'Making Tracks' articles by Dennis Monk and published in the Model Engineer magazine. The wheels on all rolling stock wishing to use the ground level railway MUST conform to the recognised standards below.

These standards are those laid down by the 7.25" Society and the Southern Federation of Model Engineering Societies, and are detailed below.

Do your locomotive and driving car wheels conform to these standards?

Wheel gauges are available to verify that your wheels conform to the CSME accepted standards.

Reference	7.25"G	5"G	3.5"G	2.5"G
A (Back to Back)	6.813"	4.687"	3.281"	2.281"
B (Root Radius)	0.125"	0.070"	0.050"	0.035"
C (Flange Tip Radius)	0.063"	0.045"	0.030"	0.020"
D (Flange Thickness)	0.140"	0.106"	0.076"	0.055"
E (Flange Depth)	0.188"	0.140"	0.110"	0.085"
F (Minimum Tyre Width)	0.813"	0.535"	0.375"	0.268"
G (Chamfer)	0.040"	0.030"	0.020"	0.015"

These standards are based on standard main line prototype locomotives. Narrow Gauge prototype locomotives will differ.

For Gauge 1 wheel standards information click here.