Griffon

Four anti-rollback dogs are visible behind the two black automotive tires.

Many of the bolts and nuts on roller coasters have a small line of paint on them.  You can see little blue stripes of paint on many of the nuts and bolts under this car.  By simply looking at the unbroken line of paint that stretches between unmovable parts of the car and the nuts and bolts, maintenance personnel can quickly check that these nuts and bolts haven't loosened.

©2018 by Joel A. Rogers.