The Soviet locomotive class IS (Russian: ИС) was a Soviet passenger steam locomotive type named after Joseph Stalin (Russian: Иосиф Сталин). The contract design was prepared in 1929 at V.V. Kuybyshev Locomotive Factory in Kolomna. The IS series locomotives were manufactured between 1932 and 1942.
The locomotive used the same cylinders and boilers as the FD series locomotives. However the IS steam locomotive had a 2-8-4 wheel arrangement.
The first steam locomotive was released from the Kolomna factory on October 4, 1932. In April–December a steam locomotive was tested on the October, Southern, and Ekaterinenskaya railways.
In 1936, production began at October Revolution Locomotive Factory in Voroshilovgrad. In total, 649 IS steam locomotives were constructed. Later the series was renamed FDP (steam locomotive FD, passenger modification).
These locomotives were used until 1972.
IS20-1 in 1932
IS20-08 in 1936
Russian locomotive class IS exhibited in Paris in 1937
The only preserved IS plinthed IS20-578 in Kiev