7¼ Inch Gauge Track/Wheel Standards
Information extracted from ”Code of Practice” document Appendix 5.
Refer to this document for more details.
| 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 | 3° | 3° | |
| 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