Deutsche Bahn

Coupler adapter strength analysis

(Derby, 7 September 2021) The Rail Operations Group needed to determine whether a coupler adapter fitted to the draw-hook of a Class 37 locomotive was fit for purpose. They needed to ensure that it could haul the required range of vehicles, withstanding the load and coping with the operational track geometry. An assessment into the expected traction and braking forces that the adapter coupler would be subjected to when hauling units was also necessary.

DB ESG was contracted to complete a strength analysis for the adapter coupler to determine whether the adapter coupler could perform its intended operation.

Work undertaken:

  • Traction and braking analysis.
  • A survey of the adapter and support frame was conducted, and a CAD model was produced.
  • Finite Element Analysis (FEA) was used to determine the static strength of the coupler adapter, using the forces determined during the traction and braking analysis.
  • FEA was also carried out on the support bracket to determine the standard static strength and strength reserve.
  • The operational track geometry was investigated. A DB ESG calculation curve analysis tool was used to analyse the geometry for the coupled vehicles that may use it. This tool allowed the coupler movement to be determined for the route, allowing the maximum coupler movement to be calculated.
  • A technical report was generated that detailed the forces that were likely to be encountered in the coupler adapter. This report detailed: -the ultimate strength of the adapter coupler
    -its reserve value over the maximum operational loading
    -the operational parameters for the hauled unit
    -compliance with the applicable standards
    -justification of any applied assumptions