It is almost banal to state the obvious, couplers are an essential part of railroad technology. They must withstand the pulling force of the locomotive as well as the buffing forces imparted by the operation of the train over a wide range of track conditions. They must be 100% reliable; breaking a train is very definitely a bad thing!
“Link and pin” couplers was the early solution to the requirement to join cars into a train that would stay together when pulled from place to place. The link and pin couplers were very dangerous to use when making up a train and many switchmen lost fingers and hands, perhaps their lives, when making a “joint”.
Many kinds of couplers were invented to replace the link and pin. Most were rejected by the railroads for various reasons. It was the invention of the Janney coupler that led to widespread replacement of the link and pin.
The Janney coupler is still in use today and making up trains has become much safer.
The link and pin shown in the gallery was discovered a I was walking on the abandoned UPRR original right-of-way, just west of Green River at “Fish Cut”. They are at least 130 years old and well represent coupler technology as it existed then.
The Old Machinist