Answer: Air brakes
Explanation: The introduction of air brakes by George Westinghouse marked one of the most important safety upgrades in railroad travel. The air brakes which is powered by compressed air connected to the braking cylinders which automatically serves air to the brake pipes once the brake pressure falls. This automatic airbrakes offered an escape from the inefficient and manual brake system usually employed before it's invention whereby brakemen are charged with the task of controlling the braking system using the brake wheel in other to alt the train's movement. This manual method is both tedious and unsafe.