As Mr. Boyd notes it was also very time consuming, requiring a few minutes to stop a train going just 15 mph. In some instances engineers could see their approaching trains but could not stop in time to avoid a collision. According to the book, Railroads In The Days Of Steam (from the editors of American Heritage), a young Union Army veteran named George Westinghouse hoped to fix this problem, improve safety, and save lives. He was particularly disturbed by the incident mentioned above which had occurred near Schenectady, New York. After some time he received a patent for an automatic air brake on April 13, 1869. His design utilized a triple valve system which included a piston valve, slide valve, and graduating valve. To increase a train's stopping time Westinghouse equipped each car with its own air reservoir (tank).
Once activated from the locomotive cab it operated on a fail-safe system; the line, interconnected throughout the train by sealed pipes running underneath each car would release its air at a controlled rate, thus reducing the pressure which then triggered a valve system on each car to feed air into the brake cylinder. After the engineer released the brake, the valve portal would close and each car's tank refilled with air. This increase in air pressure subsequently caused each car's valves to work in reverse, allowing the brake cylinders to release their pressure. During an emergency situation, such as a rapid loss of pressure via a damaged line or the engineer manually "dumping the air," braking is rapidly applied throughout the train. It was an ingenious system but, not surprisingly, railroads were skeptical.
As the Cornelius "Commodore" Vanderbilt told Westinghouse, "Do you pretend to tell me that you could stop trains with air?" He proved the legendary tycoon wrong (who laid the foundation for what eventually became the mighty New York Central System) during a demonstration run from Pittsburgh, Pennsylvania to Steubenville, Ohio. During the test he placed an air pump and tank on the lead locomotive and then ran pipes to every trailing car. Each had its own cylinder and piston connected to a braking system and once activated by the engineer the compressed air quickly applied braking throughout the train. This initial design did not employ a fail-safe system so if the line was cut or there was a leak the resulting loss of pressure would cause the brakes to fail. In 1872 Westinghouse improved upon his initial design, which is mentioned above. Unfortunately, even this demonstration did not fully convince railroads.
The issue largely came down to money as companies did not want to spend the large sums of capital required to upgrade their equipment with the new device. During the 1880s the first legislation was enacted when Iowa, led by state railroad commissioner Lorenzo Coffin, passed a measure to have all trains operating within its state equipped with both automatic air brakes and Eli Janney's new knuckle coupler. Finally, Congress passed the Railway Safety Appliance Act in 1893 requiring all railroad equipment utilize the braking system. Westinghouse went on to establish his Westinghouse Air Brake Company in 1869 and today railroads in the United States continue to use the basic system although many improvements have been made over the years (worldwide other countries have adopted a pneumatic system, such as in Britain and Germany).
Glossary And Terms
Westinghouse Automatic Air Brake