page_title: Railway coupling
section_title: Dual couplings and match wagons
hierarchical_section_title: Railway coupling / Dual couplings and match wagons
caption_attribution_description: English: An adaptor for mating differing railroad couplers, stored on a passenger platform at Pennsylvania Station, New York. The device is called compromise coupler and is used to couple NJ Transit Arrow III trains to standard railroad equipment. The Arrow III trains are fitted with a spear type coupler.
context_page_description: A coupling is a mechanism used to connect rolling stock in a train. The design of the coupler is standard, and is almost as important as the track gauge, since flexibility and convenience are maximised if all rolling stock can be coupled together.
  The equipment that connects the couplings to the rolling stock is known as the draft gear or draw gear.
context_section_description: Sometimes a wagon with one coupling system needs to be coupled to wagons with another coupling type This may be needed when taking metro rolling stock from its manufacturer to the city where it is to be used. There are two solutions:
  use a match wagon(s) which has different couplings at either end.
  use a coupling adaptor.
  Only some kinds of couplings coexist on the end of a wagon at the same time, because amongst other reasons they need to be at the same height. For example, in the Australian state of Victoria, engines had the AAR coupler, with buffers, and the chain mounted on a lug cast into the AAR coupler.
  A match wagon or match truck (also known as a "barrier vehicle" / wagon in Britain and "transition car" in North America) has different kinds of couplings at each end. If a pair of match wagons is used, a rake of wagons using coupling A can be inserted into a train otherwise using coupling B.
  A coupling adaptor or compromise coupler might couple to an AAR coupling on a wagon, and present, for example, a meatchopper coupler or rapid transit coupler to the next wagon. Such an adaptor might weigh 100 kg (220 lb).
  An adapter piece allows a Janney coupler mate with an SA3 coupler
caption: Coupling adapter for use between Janney coupler on a locomotive and WABCO N-2 couplers fitted to commuter rail multiple units at New York's Pennsylvania Station. The adapter is seen from the bottom
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