Train travel is one of the safest ways to get around. That wasn't always the case. While early railroads knew how to get big, heavy locomotives going, stopping them was another matter. That's where George Westinghouse came in.
Westinghouse invented train airbrakes, and modern trains still use his basic design. Before the introduction of airbrakes, locomotive brakes had to be applied manually: Brakemen in each car would manually apply the brakes based on signals given by the engineer. However, the brakemen couldn't always hear the signals; they sometimes applied the brakes incorrectly, leading to accidents.
Airbrakes, on the other hand, could be operated by the engineer. Compressed air in a tank is released through pipes on the underside of the train cars, and the compressed air applies the brake shoes to the train's wheels. The most innovative part of Westinghouse's design was that it was fail-safe: If the system felt a leak in the pipes, the brakes deployed automatically, stopping the train before its speed became a problem.
Westinghouse's airbrakes are still used on trains today. If you use natural gas to heat your home or cook, however, you may have a lot more to thank George for.