Tightlock coupling

TypeF tightlock couplers

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 transferred 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.[1]

Rail operators that commonly use TypeH couplers include Amtrak, Réseau de transport métropolitain, 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.

The AAR TypeF TightLock coupler[2] is a Janney automatic coupler typically used on North American gondola cars that go through rotary car dumpers as well as on some tank cars. Tank cars carrying hazardous materials are equipped with AAR TypeE double shelf couplers.[3][4][5]

Tightlock use in the United Kingdom

TypeH couplers are in widespread use on multiple unit passenger trains in the UK built from the mid 1970s onwards. The previous generation of slam door units fitted with Buckeye couplers had required a shunter to get down onto the track and stand between the two units to manually trip the coupler mechanism as well as connect or disconnect the air pipes and electrical jumper leads. In order to reduce staffing costs and cut down station dwell times, British Rail looked to incorporate an automatic coupler mechanism in its new power-door trains. Class 313 units were the first stock to incorporate this. Air-operated Tightlock couplers were chosen, together with underslung electrical connector boxes controlled by a Drum switch, and this allowed drivers to single-handedly attach or split a train without having to leave the cab.

Classes of train equipped included:

Networker Tightlock coupler

The Tightlocks were generally a success, but there were reliability issues and some notable incidents occurred where trains divided in service. The constant couple-uncouple cycles of heavy London commuter services caused the couplers' mechanisms to wear out faster than expected. Connex South Eastern's Networker fleet was particularly susceptible to this and the company blamed its drivers in the media,[6] then changed its coupling instructions to drivers to include a "push-on, pull off" power test and visual inspection to ensure that the knuckles had engaged fully.

By the early 2000s the first batch of Bombardier Electrostar Class 375s had been built with tightlock couplers for Connex South Central and Connex South Eastern, but it was quickly decided that Dellner couplings[7] would be preferable. All subsequent units were built with these, and their earlier examples were eventually modified.

All multiple unit trains built for the UK since then have been equipped with Dellner couplings.

See also

References

  1. ↑ AAR Manual of Standards and Recommended Practices, Section S, Part I:Casting Details, Issue 06/2007
  2. ↑ TypeF coupler
  3. ↑ TypeE double shelf
  4. ↑ "Columbus Castings Couplers and Yokes". Archived from the original on 2013-05-30. Retrieved 2013-05-26.
  5. ↑ "Archived copy" (PDF). Archived from the original (PDF) on 2014-03-10. Retrieved 2013-05-26.
  6. ↑ BBC News: Connex blames its drivers as trains come apart
  7. ↑ Dellner Couplers AB — Automatic and Semi-Permanent Couplers
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