Standard RP4: Wheels - Proto:64

Check Gauge maxmium	Kmax	0.851"	21.62mm
Back to Back minimum	Bmin	0.824"	20.94mm
Tire Width minimum	Nmin	0.087"	2.21mm
Flange Depth maximum	Dmax	0.026"	0.66mm

Standards and Clearance Diagrams

• Track and Wheel Standards - NASG/NMRA standards
  • Track, Standard Gauge S 3
  • Track, Narrow Gauge S 3.5
  • Wheels, Standard Gauge S 4
  • Wheels, Narrow Gauge S 4.5
  • Track, Proto: 64 RP 3
  • Wheels, Proto: 64 RP 4
  • The NASG Clearinghouse offers track and wheel gauges for S standard gauge.
• NMRA Standards
  • standard-gauge NMRA turnout dimensions (RP 12.3)
  • The NMRA recommended practice for car weight is 2 oz. plus another 1/2 oz. per inch of car length.
  • Sn3 track and wheel gauges are available from the NMRA.
• Clearance Diagrams and Gauges
  • older (pre-stack car era) clearance template (PDF)
  • newer " Plate H" clearance template (PDF)
  • If you prefer to purchase a clearance gauge instead of making one, S clearance gauges are available from banta modelworks made of either wood or acrylic.