Trains and Railroads
Brakes And Couplers
Early cars were coupled together using a link and pin system. Given that the pins had to be put into place and removed manually while the cars were moved by a distant engine, coupling cars was a dangerous job that all too often led to the loss of fingers and hands. Alternate coupler designs were proposed, and in 1887 a coupler designed by Eli H. Janney was approved by the Master Car Builders' Association. Resembling the curled fingers of two hands, Janney's coupler allowed cars to hook together without the use of pins.
Brakes, too, were a problem with early trains. They had to be applied on each car by hand, a time-consuming process. Brakemen on freight trains had the added difficulty of applying the brakes from a precarious perch on the top of the car while hoping that the train did not go under any low bridges. In 1869, George Westinghouse patented an air brake that used compressed air to force the brakeshoes against the wheels. Each car had a reservoir of high pressure air (70-100 lb [32-45 kg]/sq in). A control pipe filled with compressed air ran the length of the train. If the pressure in the control pipe dropped, the compressed air in the reservoir applied the brakes. This could occur when the brakes were applied or when a car became detached from the train—an added safety measure.
When diesel and electric locomotives came into use, a different approach to braking was possible. Both types of motors can be reversed such that the motor is working against the motion of the train. This dynamic braking system allows minimal use of air brakes, with longer wear on the brake shoes. Some high speed trains have computerized braking systems. If the engineer exceeds permitted speed on a section of line, the brakes are automatically applied.
Locomotive brakes took much longer to catch on than railcar brakes. Robert Stephenson's 1833 Patentee design included specifications for a steam brake, but the earliest recorded use of a brake on the driving wheels of an American locomotive was in 1848. Development and implementation was sporadic throughout the 1860s and 1870s, but by 1889 about half of all American locomotives were equipped with driving wheel brakes. By the end of the century, locomotives were routinely equipped with brakes, a necessity given the increased power and speeds of the twentieth century engines.
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