Deutsche Bahn

Design and testing of coupler adapter to Class 67 and 66 Locomotives

for Hitachi Rail Europe


Hitachi Rail Europe required a special mechanical conversion adapter to be designed to allow a class 67 and 66 locomotive to connect to, and haul, a Class 385 unit (ASR unit). This adapter needed to interface between an AAR coupler on a Class 66/67 locomotive and a Dellner coupler on the ASR unit. The adapter needed to haul the ASR unit at speed with the use of a brake interface unit between the locomotive and the ASR unit.

Work Undertaken

As part of the design verification, DB ESG needed to ensure that the adapter had sufficient capacity to withstand the expected traction and braking forces associated with being coupled to the AAR swing head coupler. They also undertook a movement and force analysis on the coupler adapter to ensure that the coupler was fit for purpose. Work included:

  • Calculating the tensile and compressive forces within the adapter coupler
  • Determining the maximum coupling speed
  • Working out the tensile and compressive forces due to the acceleration of the locomotive and the differential braking rates between the locomotive and hauled unit
  • Determining the effects of the gradient on the coupler
  • Calculating the running resistance
  • Analysing the coupler movements resulting from the geometry of the adapter, the vehicles and traversed track.
  • Obtaining all necessary approvals and certification via DB ESG’s sister company, Railway Approvals Ltd.

DB ESG were able to determine the design parameters and verify that the coupler adapter was fit for purpose and that the maximum forces within the coupler adapter were within its capacity. DB ESG determined, through movement and force analysis, the geometric parameters of the adapter, ensuring it was able to haul the ASR unit with a class 66/67 locomotive over the range of track geometries that the AST unit was designed to negotiate. This ensured no movement resitrictions needed to be appled over and above that required for the ASR unit.

Note for editors: 

For media enquiries contact Heidi Lee, Marketing and Communications Manager, DB ESG –  01332 483 849 (mobile - 07870 958043) or email:

About ESG Rail - ESG Rail is the route to market for DB’s technology expertise. As part of the DB Group, ESG provides innovative, value-led strategic advice, technical consultancy and technology integration. Based in Derby, home to the largest cluster of railway companies in the world, ESG is a leading rolling stock consultancy and provides services to many of the UK’s train operators, manufacturers, owners and maintainers.