The job: Historically, railway brake operators were responsible for slowing a train by applying handbrakes to individual train cars. At a conductor's signal, brakes were manually applied or released using large brake wheels located at the end of each car. Brakemen also operated railway switches, enabling a train to change tracks and alter course.
Killed by: Automatic air brakes. In 1869, George Westinghouse invented the first direct-air brake sytem, which allowed the central train engineer to control a train's entire braking system. When Congress passed the Railroad Safety Appliance Act in 1893, automatic braking and coupling systems became mandatory on all U.S. trains. Brakemen, at least in their original form, became obsolete. Today, the brakeman position lives on in name and limited number, but manual braking is no longer part of the job description.