and on the Matangi trains of Wellington's. It also equips all the dedicated rolling stock used for the shuttle services in the Channel Tunnel. Maximum tonnage under . Voith and Dellner are working on an automatic coupler based on Schaku, a possible replacement of the buffers and chain coupling on European railways. Automatic Buffing Contact Coupler Automatic Buffing Contact (ABC) Coupler Dellner coupler The Swedish-made Dellner coupling, is a proprietary version of the Scharfenberg coupler, connecting vehicle, pneumatics and electronics at the same time. The patented energy absorption D-BOX technology allows coupling at speeds of up to with no structural damage, and up to with deformation but with the vehicles remaining on track. The patented D-REX system provides Ethernet high speed data connection at speeds of 100 Mbit/s. Ward coupler Ward coupler Wedgelock coupler The Wedgelock is the standard coupler on London Underground trains. The origin of the Wedgelock principle is unclear; however, there are a number of variants, many of which were once produced by the now-defunct Associated Equipment Company (AEC) in Southall, London. Wedgelock intellectual property was acquired in 1979 by Radenton later (in 1994) to become Radenton Scharfenberg. Basic design and coupling principle: The older coupler design has a body consisting of two horizontal steel plates separated by shaped blocks to create two pockets the one on the right (driver's perspective) has a vertical pin to anchor a shaped hook protruding forward of a front plate bolted to the body. The second void in the left of the body contains a cylindrical pin with a large flat to create a D-shaped cross-section. The hook is free to swing left and right through an arc of about 5 degrees and can engage with the D-pin in an opposing coupler. During coupling, once opposing front plates are in contact, a pneumatic actuator within the left-hand void drives a (partially) wedge-shaped block behind the outer edge of the opposing hook to engage it with the host D-pin. The sloping wedge geometry occupies the central horizontal third of the block and contacts a similar horizontal sloping groove in the opposing hook merely to engage it with the D-pin. The upper and lower thirds of the wedge have pockets machined to create faces parallel to the longitudinal axis of the coupler. As the wedge is caged by body structure it is these faces which prevent sideways movement of the opposing hook and