1.   As the vessel shot along the track and crashed through the sphere, the pole tripped switches setting off pyrotechnics that make the ship appear to be burning.

2.   About three-fifths of a mile from crossings, oncoming trains trip a switch that activates signals and lowers gates.

3.   If the skier loses control and takes a fall, a cord attached to their lifejacket is pulled out, tripping a switch that shuts off the engine.

4.   Some breakers have a small window that exposes a red flag when the switch is tripped.

5.   This trips the switch and opens the contacts that allow electricity to flow.