SA3 Coupler

The SA3 coupler is a type of railway coupling used mainly, but not exclusively, in Russia and other states of the former Soviet Union.

Railways in Russia used European (British) buffers and couplings from their inception. These couplings had three main limitations. Firstly the load was limited. Secondly, the couplings were not automatic like the North American AAR. Thirdly, the buffers could get buffer-locked and cause accidents. Advantages and disadvantages of these couplings are intermediate between AAR couplers and Scharfenberg couplers.

It took a while to find a replacement. One option was to copy the AAR coupling, as Japan (1922), Australia (1915) and other countries were starting to do, or to devise something else. The Soviets were not afraid to copy, as they had imported many engines and engineers during the various five year plans. In the end they chose the SA3, although implementation was delayed by World War II.