NMRA standards provide the primary basis upon which Interchange between equipment and various North American scale model railroads is founded.

Model train gauges with the NMRA standards provide model railroaders a way to check all important dimensions of a track and rolling stock as follows:

• Gauge of track and turnouts
• Flangeway depth and "check gauge"
• Clearance
• Height of loading platform 

 
If cars do not run correctly, these NRMA gauges will help you pinpoint the trouble.

The pocket size model train gauge is a railroad tool that should be in every serious modeler's kit.