SA-3 (central buffer coupling)
The coupling SA-3 , Russian Автосцепка СА-3 , is a semi-automatic central buffer coupling , which is mainly used in the former Soviet states. It is also used in Finland , Iraq , Iran and on the ore railways in Sweden and Norway for iron ore transports, where the conventional European screw coupling would be overwhelmed by the maximum pulling force.
Technically, the SA-3 is a further development of the Willison coupling .
history
After all railways in North America had been obliged to use the semi-automatic Janney coupling since 1898 (with extended transition periods since 1900 at the latest) , the UIC, founded in 1922, also set up a working group in 1928 to develop such a coupling. However, since the planning did not go beyond a definition of the requirements and instead expanded these requirements to an unrealizable level, the Soviet Union decided to go it alone on a national level.
In Germany, Scharfenberg couplings had proven to be unsatisfactory in terms of loading capacity and weather resistance (icing) in coal trains. John Willison had his clutch patented in England in 1910, then in the USA and Germany in 1916. Knorr took over the patent and used it for couplings in Germany and on suburban trains from Paris.
The very robust concept of the American Willison was then adopted for the Soviet Union, which called the clutch type SA-3 (the abbreviation from Russian Советская автосцепка, 3-й вариант , Soviet automatic clutch, third variant).
After the concept was decided in 1932, the conversion of the vehicles began successively in 1935. The Second World War delayed the introduction so that the conversion was not completed until 1957.
After the Second World War, Europe was divided into a west-oriented and an east-dominated state system. The victorious powers introduced many of the social and technical standards of their home countries in the areas they liberated and in the occupied areas of Germany they administered. Under these conditions, further developments of this type of coupling began in 1955 in Bautzen Waggonbau for the OSJD . In 1970 this work led to a central buffer coupling standardized by the UIC , which is still compatible with SA-3.
