Prior to the advent of trucking in the early 1900s, rail was the only efficient way to transport goods over land. However, before the 1870s, there was no easy way to quickly stop the extremely heavy freight trains. Brakemen scrambled over the tops of moving cars to activate hand brakes on each one. The system was unreliable, resulting in frequent derailments, and many brakemen were killed or maimed after falling from trains. The air brake solved all of those problems. How did it work? Discuss
Source: The Free Dictionary