Janney couplers are a semi-automatic form of railway coupling that allow rail cars and locomotives to be securely linked together without rail workers having to get between the vehicles. They are also known as American, AAR, APT, ARA, MCB, knuckle, Buckeye, tightlock (in the UK), Henricot (in Belgium) or Centre Buffer Couplers.
Background
Janney couplers were first patented in 1873 by Eli H. Janney (). Andrew Jackson Beard was amongst various inventors that made a multitude of improvements to the knuckle coupler; Beard's patents were granted 23 November 1897, which then sold for approximately $50,000, and granted 16 May 1899.
In the UK, several versions of Janney couplers are fitted to a limited number of coaches, multiple units, wagons and locomotives.
Janney Type E, Type F Interlock, and Type H tightlock couplings are compatible subtypes, each intended for specific rail car types.
Prior to the formation of the Association of American Railroads (AAR) these were known as Master Car Builder (MCB) couplers. In 1934, the MCB was renamed as the AAR.
Knuckle couplers of the 1880s and 1890s had a chaotic mixture of proprietary internal components, but all had the standard MCB external contour, making them compatible. There was a multitude of makes and models — Burns, Climax, Gould, Miller, Sharon and Tower. Some worked better than others.
In 1913, American Steel Foundries (ASF) developed the Janney "Type D" coupler, that was then made the MCB standard coupler for North America; new and rebuilt rolling stock had to be fitted with that coupler. That ended the market for knuckle couplers with proprietary components, excepting those exported from the US to other countries not complying with MCB standards.
The Alliance coupler, named after the ASF-owned foundry in Alliance, Ohio, was developed as a lighter build than the "Type D", and was marketed by the Amsted Corporation, parent of ASF, as the "Standard for the World". It is still the most-used knuckle coupler in the world. The modern Alliance coupler still uses the modern AAR-10 or 10A contour, but has a shorter thus weaker head length, and thus cannot be used on North American interchanged rolling stock.
Manufacturers of modern "Type E", "Type F Interlock" and "Type H Tightlock" couplers include McConway & Torley, ASF, and Buckeye, also known as Columbus Castings.
The external contour of Janney knuckle couplers was the first aspect to be standardized by the MCB in the 1880s. Prior to this, there was a chaotic variety of constantly evolving and proprietary external contours and internal components. In 1893, manufacturers standardized on the MCB-5 or Type C contour, then in 1915 on the improved MCB-10 or Type D contour, and again in 1932 on the AAR-10A or Type E contour. The 1893, 1915, and 1932 contours are measurably different with slight dimensional changes that improved performance, yet remain compatible. Janney couplers still use the 1932 contour, though tolerances, metallurgy and machining techniques have improved, resulting in notable reductions in coupler slack. Type H tightlock couplings used on passenger stock have a variation of the 10A contour that nearly eliminates slack during normal operation and minimizes the possibility of "telescoping" during a derailment.
Purpose
The purpose of couplers is to join rail cars and locomotives to each other so they all are securely linked together. Major Eli Janney, a Confederate veteran of the American Civil War, invented the semi-automatic knuckle coupler in 1868. It automatically locks the couplers on cars or locomotives together without a rail worker having to get between the cars, and replaced the link and pin coupler, which was a major cause of railroad worker injuries and deaths. The locking pin that ensures Janney couplers remain fastened together is withdrawn manually by a worker using the "cut lever", which is operated from either side of the railroad car and does not require the person to go between the cars. The only time the worker has to go between cars is after they have been securely coupled, to hook up the air lines for the pneumatic brakes, and the head-end power cables in the case of passenger cars.
Modern Janney couplers typically mount to rail cars and locomotives via draw gear; early Janney couplers often had transitional shanks which mounted into legacy link and pin coupler pockets, or bolted directly to steam locomotive headstocks.
Janney/MCB/ARA/AAR/APTA coupler
The Janney coupler is used in the Americas, Australasia, Africa, Asia, UK, Belgium and Spain (narrow gauge railway only).