7¼ Inch Gauge Track/Wheel Standards

Information extracted from ”Code of Practice” document Appendix 5.
Refer to this document for more details.

7¼in Gauge profiles

 

Standard Track Dimensions:
Imperial Metric (mm)
Track Gauge (Nominal) 7.25" 184.15
Track Gauge (Actual) 7.28" 185.00
Check Gauge 6.83" 176.00
Check Rail Spacing 6.57" 167.00
Width of Flangeway 0.35" 9.00
Gauge Clearance 0.20" 5.00
Gauge Widening (Curves <20m radius) 0.12" 3.00
Railhead Edge Radius 0.04" 1.00
Depth of Flangeway (minimum) 0.32" 8.00
Wheel Check Clearance to back of wheel 0.06" 1.50
  Practical tolerance: ±0.5mm

Standard Wheel Dimensions:
Imperial Metric (mm)
Back to Back (BB) 6.69" 170.00
Flange Depth 0.24" 6.00
Flange Thickness (FT) 0.20" 5.00
Flange Angle - Front 20° 20°
Flange Angle - Rear 0 - 8° 0 - 8°
Wheel Check (BB+FT) 6.89" 175.00
Wheel Root Radius 0.08" - 0.12" 2.00 - 3.00
Wheel Tyre Taper
Wheel Tyre Width (minimum) Fine scale 0.80" 20
Narrow gauge 0.98" 25
Flange Tip Profile Half round
  Practical tolerance: ±0.25mm

Rolling Stock Dimensions:
  Metric (mm)
Coupler Height (above rail)   125
Drawbar X-section (minimum)   25 x 8
Coupler Pin Diameter (minimum)   10
Running Gauge Clearance (minimum)   16

 

17 June 2009