The Scharfenberg coupler (, abbreviated Schaku) is a commonly used type of fully automatic railway coupling.
Designed in 1903 by Karl Scharfenberg in Königsberg, Germany (today Kaliningrad, Russia), the coupler has gradually spread from transit trains to regular passenger service trains, although outside Europe its use is generally restricted to mass transit systems. The Schaku is superior in many ways to the AAR (Janney/knuckle) coupler because it also automates electrical and pneumatic connections and disconnections. However, there is no standard for the placement of these electro-pneumatic connections. Some rail operators have placed them on the sides while others have placed them either below or above the mechanical portion of the coupler.
Working principles
The face of the Scharfenberg coupler has a protruding cone and a matching cup. Inside the cone there is a rigid metal hoop connected to a revolving, spring-loaded metal disk with a notch on the opposite side. When ready to couple, the spring turns the disk so the hoop is extended from the cone. As the cars meet, the hoop enters the cup on the other coupler, stopping against the disk. The hoops are then pressed back into their own coupler, causing the disks to rotate until the notches align with the hoops. After the hoops have entered, the notches on the disks spring back into the hoop extended position, locking the coupling. In the coupled position, forces on the hoops and disk will balance out, which means that the Scharfenberg, unlike many other couplers, is not dependent on heavy latches to stay locked.
Small air cylinders, acting on the rotating heads of the coupler, ensure the engagement of the components, making it unnecessary to use force to get a good coupling. Joining portions of a passenger train can be done at very low speed (less than in the final approach), so that the passengers are not jolted. One problem with the coupler is that it is often hard to connect it in a curve. Planned coupling is normally done on a straight flat track, while there has been trouble coupling a broken down train at an unplanned place.
Uses
Rail equipment manufacturers such as Alstom offer the Schaku as an option on their mass transit passenger cars and locomotives. Presently, Scharfenberg couplers are in use on the following passenger transit systems:
Australia
Victoria - V/Line (VLocity 160, Sprinter), Metro Trains Melbourne (Comeng, X'Trapolis 100 [also used in Chile]) New South Wales - Sydney Trains (T, M, A & B sets) New South Wales - NSW TrainLink (Endeavour railcar and Xplorer) Western Australia - Transperth (A-series, B-series train) South Australia - Adelaide Metro (3000 class railcar) Queensland - Queensland Rail (EMU, ICE, SMU, IMU, NGR)
Spain
Renfe commuter, regional and high speed trainsets and multiple units
Talgo III trainsets (now retired) Euskotren EMUs FGV trainsets Madrid, Barcelona and Bilbao metros (some are used only if a train needs to be towed) CAF Urbos trams (towing only, some adapted with electric connections) Iryo and Ouigo high speed trainsets Feve (now renfe) electric and diesel multiple units
Saudi Arabia
Haramin High Speed Train - Talgo 350 train
United States
San Francisco Bay Area - BART (New Type D and E vehicles) San Francisco Bay Area - Muni Metro (New Type 4 vehicles) Denver - RTD Bus & Rail (New light rail vehicles) Baltimore - Baltimore Light Rail (New light rail vehicles) New Jersey - New Jersey Transit (New light rail vehicles) Portland, Oregon - TMTC (Light rail vehicles) Minneapolis - METRO (Light rail vehicles) Norfolk, Virginia - HRT (Light rail vehicles) San Diego County, California (NCTD Sprinter light rail)
Canada
Montreal - Metro
Vancouver - Skytrain
Toronto - Scarborough RT
Europe
Thalys
TGV – All French high-speed trains are equipped with Scharfenberg type 10 couplers. ICE – All German high-speed trains are equipped with Scharfenberg type 10 couplers. Many regional train EMUs and DMUs in Europe Rhine-Ruhr Stadtbahn - Almost all German light-rail and streetcar systems use Scharfenberg couplers. SBB Cargo – In 2019, the swiss freight operator introducing cargo wagons with Voith CargoFlex, an extension of Scharfenberg type 10 couplers. Channel Tunnel - Eurotunnel Le Shuttle Narrow-gauge railways in Saxony, Germany