The AAR/APTA TypeH TightLock coupler is a Janney automatic coupler typically used on North American mainline passenger cars. TypeH couplers have mechanical features to reduce slack action and improve safety, but remains compatible with Janney/AAR TypeE and TypeF couplers. TypeH couplers may also be fitted with automatic air and electrical connections. Management and development of TypeH coupler standards have been tranferred from the AAR to American Public Transportation Association (APTA). The AAR/APTA standard mounting height for TypeH couplers is 34.5 inches (876.3 mm) ATOR.
Rail operators that commonly use TypeH couplers include Amtrak, Agence métropolitaine de transport, GO Transit, Via Rail and West Coast Express. TypeH couplers have also seen very limited use on British Railways electric multiple units (EMUs) such as the Bombardier "Electrostar", though recently, Dellner or Scharfenberg couplers are being used instead.
TightLock coupler on a MBTA commuter car.
TightLock coupler on a British Rail Class 321. The electrical connector below the coupling is typically not used in North America.
 See also