Buckeye coupling on train carriage. This automatic coupler, when in its horizontal position, couples railway rolling stock together to form a train. It consists of a massive steel block with a hinged jaw or 'knuckle' at the end. Here, the device is hanging downwards on an uncoupled railway carriage. The Buckeye coupling was invented in the USA in 1879 by Eli Janney. The name comes from the nickname of Ohio, the 'Buckeye' state, where the original manufacturer of the coupling, the Ohio Brass Company, was based. A Buckeye coupling weighs almost 90 kilograms. Photographed in the UK.