Rail Mount Portable Blue Flag Protection Sign

This gauge is used to remotely measure the side bearing clearance on freight cars.
The gage is 6 foot long, It may be used from either the side or end of the car.
Turn the adjustment knob on the end of the gauge clockwise to collapse the gauge fingers to their retracted position
From either the side or end of the freight car, move the gauge into position between the truck and freight car body bolsters
Turn the gauge adjustment knob counter-clockwise until both fingers are tight against the truck and body bolster surfaces
Remove the gauge, and use a tape measure or ruler to measure the distance between the gauging fingers.