It was easy to make trains go. Speeds increased with evey passing year. But stopping trains was another matter.

Brakemen did their best with early hand brakes, but to be brutally frank, the only way to stop a traain quickly was to run into something!  Then in the late 1860s, young George Westinghouse found the answer.

Westinghouse's "air brakes" were first tested in 1868. Cornelius Vanderbilt dismissed the invention as a "fool idea". The tests were highly successful.

Here is how the air brakes work:
Compressed air in Tanks (A) and (B) is under equal pressure. When the Air Control Lever is opened, Valve X cuts off Tank (B) allowing air in the exhaust, and on the right side of the Control Piston to escaape.

Pressure to the left forces Control Piston to the right, clossing Valve Y. This pulls the Shift Piston across Valve W and closes Vale Z.

This allows air from Tank (A) to rush into cylinder pushig the brak Piston and stopping the car.