The gauge should be a friction fit - if not adjust the wheels on the axles or replace if necessary. TT Wheel Gauge - Back to Back.
2 Pack - OO Gauge (1:76) Back to Back Wheel Gauge Tool 14.4mm
2 Pack - TT Gauge (1:120) Back to Back Wheel Gauge Tool 10.24mm
Back to Back Wheel Gauge 7.65mm N Gauge GOLDEN VALLEY HOBBIES GVB2BN
Golden Valley Hobbies GVB2BOO Back To Back Wheel Gauge 14.4mm OO Gauge
Back To Back Wheel Gauge 14.4mm For OO Scale
Back To Back Wheel Gauge 7.65mm For 009/N Gauge (Pack of 2)
