Hardly an other component of railway equipment was tested in such a comprehensive scale as the prototypes of centre coupler.

There were a lot of reasons for this:

• The coupler was a complete new and complicated item for the railways: A mechanical automatic coupler, automatic devices included simultaneous coupling of pneumatically and electrical lines, a new central draft gear with high capacity, a elastic centring device, operating device etc.
• The coupler has an high impact to safety and availability of rolling stock
• All participating railway administrations need 100 % proof to stand all requirements stated in the specification.

After separate developments of centre coupler by OSShD(East)- and by UIC(West) Railway Organization in 1963 started the project to unify the two systems to get ability to couple together. This and the demand to guarantee function with the Russian SA3 - coupler resulted in big numbers of test series with all combinations between the three coupler types.

Other problems resulted from the fact, that in this time the 'Cold War' between the super powers was in full run. Often test, test interpretations and technical development too, were influenced by political, tactical, and patent under law considerations. Thanks to the skill and flexibility of the participated engineers and negotiating partners a solution, acceptable for both sides, was worked out and was tested successful.

• Tests at stationary test benches:
  • At geometrical test benches to simulate sliding in and coupling with defined horizontal and vertical differences between, including different vertical and horizontal angle combinations.
  • Static load test benches to verify stress and pressure strength
  • Dynamic test benches to verify shock resistance and resistance against wear by simulating long service periods.
• Tests with single wagons and with trains, equipped with centre couplers
• Tests to verify safety against derailment
• Running tests to verify running behavior and function of line connectors
• Test in extreme cold conditions
• Tests in gravity yards and coupling test with different coupling speeds, different loads, at straight and curved tracks
• Special tests
• Tests at ferry boat platform
• Tests with the mixed mechanical couplers (developed for a period of transition between wagons with centre coupler and wagons with side buffers and draw hook).
• Couplings tests with high-speed cameras, to study special functional behavior