When railroading was new there were many "bugs" in the ooperation, just as it is  with anything that has been untried. One of the more serious problems dealt with car couplings. In te beginning cars were hooked together with a link-and-pin coupler. This system required a brakeman to stand between the cars and inseret the pin in the link as the cars were pushed together. If he failed to insert the pin and make the couple at the right split-second he might lose s few fingers, or hand or arm, or even be crushed to death between the moving cars. Link-and-pin couplers also allowed for excessive sway when the cars were in motion.

The answer came in 1868 from an ex-confederate soldier, Eli Janney. He developed a "knuckle" coupler that hooked upon contact, with the brakeman the couple from a safe distance.