The first safe, economical and effective train brake system was invented by inventor and manufacturer George Westinghouse and patented in 1869. Prior to this development mechanical brakes were used which had to be individually applied to each car by trainmen. Westinghouse's brake system used compressed air to actuate brakes on each car from a central control valve. This resulted in a system that was substantially more effective, more controllable and quicker, particularly in emergencies. It also avoided having trainmen jump between cars.

In 1869 Westinghouse offered his airbrake to the New York Central and the Erie Railroads, but neither was interested. He then talked the general superintendent of the Panhandled Railroad into letting him use his brakes on the Steubenville, Ohio, accommodation train. As the train emerged from Grant's Hill in Pittsburgh, the engineer looked up to see a huckster's cart on the track. When the brake valve was yanked by the engineer the train stopped 10 feet from the cart. This was the first emergency stop in railway history.

Following this testing it immediately became a commercial success. By 1905 over 2 million freight, passenger, mail, baggage and express cars and 89,000 locomotives used improved versions of the air brake. This led to the formation of the Westinghouse Air Brake Company. As technology improved Westinghouse went from making the air brake to producing an electro-magnetic brake. Besides air brakes, the company invented a rerailing frog, which helped a locomotive drag cars back onto the rails and a railway signalling device. This was the beginning of a major industrial development that led to Westinghouse's control of 30 companies and operations around the world.

The development of the air brake system made a major contribution to increasing rail safety. It also allowed the speed of train travel to increase with the knowledge that the air system would allow effective stopping.