This picture shows some of the many safety features of a modern roller coaster. Each car has multiple wheels above, below, and inside the rails. Many of the nuts and bolts use castellated nuts with cotter pins which positively lock the nuts in place. Other nuts have a line of colored paint on the nut and the bolt. The misalignment of this dab of paint would show that a nut has been loosened. And even though a beefy hinge joins the two cars, two steel braided cables sit on either side of the hinge to act as a fail-safe in order to keep the cars connected.
©2014 Joel A. Rogers.