Janney clutch
The Janney coupling is an automatic coupling for rail vehicles , used extensively on the railways in North America and in southern Africa . It is the most resilient type of coupling and also enables the formation of kilometers of trains.
background
The American Eli Hamilton Janney designed the automatic clutch named after him in 1868 and patented it in 1873. From 1877 the coupling was used on railways in the USA; In 1888, with a slight modification, it became the standard coupling of the US railways. Since March 3, 1893, all railroad companies in the United States have been required to use the Janney coupling. In the course of the following decades, the coupling became larger in order to transmit higher tensile forces, but function and form are still derived from the original Janney coupling.
In its original version , the Janney coupling is a non-rigid coupling . The two couplings form a rigid connection in the longitudinal direction; Differences in height, be it due to track errors, changes in inclination or different loading conditions, can be compensated by the coupling heads thanks to their mutual vertical mobility. An automatic connection of pneumatic and electrical lines is not possible with it.
In the USA this coupling is almost always referred to as "Automatic Coupler". It is officially called AAR Coupler (AAR is the abbreviation of the Association of American Railroads standards organization ) or Knuckle Coupler . There are several compatible versions of this coupling, the non-rigid version, which is used in particular in freight traffic, is listed by the AAR as "Type E". The type F, also known as the tightlock coupler, is often used in passenger transport in the USA for passenger trains and railcars because it does not transmit unpleasant vibrations between the cars. This form is a rigid coupling, the coupling heads are also mounted in the floor frame so that they can move in height and are held horizontally by a spring-loaded support in the uncoupled state. The rigid connection makes it possible to equip it with line couplings. Usually these are to the side or under the mechanical coupling.
Janney couplings are widespread worldwide, especially on the North American continent as well as in China, Korea, Japan and Southeast Asia. In contrast, this type of construction is rare in Europe. It is used here particularly in Great Britain for passenger coaches and railcars. Starting with the Mk-1 wagons, which emerged shortly after British Rail was founded, the passenger wagons were equipped with reinforced tow hooks that could also introduce compressive forces into the floor frame, instead of the coupling chain, hinged Janney coupling heads and longitudinally adjustable side buffers. These and the following types of wagons were connected to one another with the claw couplings and buffers shifted to the rear. For coupling with screw-coupled vehicles, the buffers were pulled out and locked and the coupling heads folded down. Locomotives were later equipped in this form, up to the high-speed locomotives of the 91 series.Multi-units were also equipped with Janney claw couplings at an early stage, and very soon with additional lateral rigidity devices as in the AAR type F. In Belgium, the Janney coupling was and is also and used in particular in railcars.
In Germany, this type of coupling was used on the narrow-gauge railway Eisfeld-Schönbrunn and the narrow-gauge railway Hildburghausen-Lindenau-Friedrichshall in Thuringia.
safety
The Janney coupling was a significant safety improvement for the North American railway personnel compared to its predecessor, the funnel coupling . During the coupling process, a shunter had to guide the coupling iron of one car into the slot of the next while the locomotive pushed the cars together; then a bolt was put through. Many accidents happened in the process; Between 1877 and 1887, around 38 percent of all accidents with injuries occurred during the coupling process. In 1902, nine years after the introduction of the automatic clutch, this value had fallen to four percent.
One disadvantage is that the Janney coupling is not always ready for coupling. To make the coupling ready, if both coupling heads are locked, an employee must step into the track and manually unlock and open one of the two coupling heads to be connected. The Willison coupling developed a few years later and types derived from it such as SA-3 are always ready to be coupled due to the drop wedge principle.
Dome head unlocked and ready for coupling
Dome head locked
Height offset between non-rigid dome heads due to track position errors
AAR type F with integrated side rigging devices
Dome head with stiffening organs and line coupling
