Golden Valley Hobbies N Gauge Wheel CheckerN Wheel Gauge - Back to Back. 7.4MMScale: NThe Wheel Gauge checkes the back to back measurements of model railway wheels.Getting the right dimension ensures the rolling stock travels through points and crossing without derailing or generating excessive movement and noise.Our gauge is set to 7.4mm - the correct width for standard N gauge track. It's ideal for all Hornby, Bachmann and Dapol etc items. The gauge should be a friction fit - if not adjust the wheels on the axles or replace as necessary.Brand: Supplier Code: GVB2BN