Couplers
The earliest cars were joined together with chains or iron bars. Later cars used many different types of couplers, including the "link and pin." A foot-long iron oval, or link, fit into horizontal slots on the ends of adjacent cars, and was held in place by vertical pins through the slots and link. Because it required switchmen to go between cars to place or remove pins, many men lost limbs.
The modern "knuckle" coupler was patented by Major Eli Janney in 1873. Each coupler has a moveable knuckle. When cars come together with one or both knuckles open, the couplers join and lock together as the knuckles close. To uncouple, the knuckle is opened by a lever accessible from alongside the end of the car.
The Janney coupler was tested in the mid-1880's and selected over 41 other designs by the Master Car Builders Association. Its use was required by the 1893 Federal Safety Appliance Act. All modern couplers are variations on Janney's original design.
Courtesy hmdb.org
