SSMRS Standard Gauge Wheel and Track Standards
  | 
        Description  | 
        Prototype  | 
        S Scale  | 
        S Coarse  | 
    |
A  | 
        Tyre Width | 5 1/2"  | 
        0.086"  | 
        0.125"  | 
    |
BB  | 
        Back-to-back | 4' -5 5/8"  | 
        0.838"  | 
        0.781"  | 
    |
C  | 
        Tyre Coning | 3°  | 
        3°  | 
        3°  | 
    |
D  | 
        Flange Depth | 1 1/8"  | 
        0.018"  | 
        0.039"  | 
    |
E  | 
        Flange Width | 1 1/8"  | 
        0.018"  | 
        0.039"  | 
    |
F  | 
        Chamfer Depth | 1/4"  | 
        0.004"  | 
        N/A  | 
    |
| Flange/Tread Radius | 5/8"  | 
        0.010"  | 
        0.020"  | 
    
It is recommended that rolling stock utilises some form of springing or compensation when using the scale wheel profiles with the 0.018" flanges.
Exact "S" Scale Track Standards  | 
    ||||||||
  | 
        Description  | 
        Prototype  | 
        S Scale  | 
    |||||
G  | 
        Gauge  | 
        4'- 81/2"  | 
        0.884"  | 
    |||||
BB  | 
        Back-to-back  | 
        4' -5 3/8"  | 
        0.838"  | 
    |||||
CG  | 
        Check Gauge  | 
        4'- 61/2"  | 
        0.856"  | 
    |||||
FW - Flangeway (Gauge Widening)  | 
    ||||||||
Gauge  | 
        Flangeway  | 
        Radius  | 
    ||||||
Prototype  | 
        S  | 
        Prototype  | 
        S  | 
        S Scale  | 
    ||||
4'-81/2"  | 
        0.884"  | 
        13/4"  | 
        0.028"  | 
        Straight  | 
    ||||
4'-83/4"  | 
        0.888"  | 
        2"  | 
        0.032"  | 
        10'3"- 7'2"  | 
    ||||
4'-9"  | 
        0.892"  | 
        21/4"  | 
        0.036"  | 
        7'2" - 5'8"  | 
    ||||
4'-91/4"  | 
        0.896"  | 
        21/2"  | 
        0.040"  | 
        Under 5'8"  | 
    ||||
The dimensions of prototype rail sections are given on a separate page. Turnout dimensions are given on another page which reproduces the data from Table 7 in "British Railway Track Bullhead Supplement" (published by The Permanent Way Institution in 1991) for prototype bullhead turnouts from the grouping era companies.  |