The Soviet locomotive class IS (Russian: ИС; Ukrainian: Паровоз ІС, romanized: Parovoz IS) was a Soviet passenger steam locomotive type named after Joseph Stalin (Russian: Иосиф Сталин; Ukrainian: Йосип Сталін, romanized: Yosyp Stalin).

The last one was built in 1942 during the Great Patriotic War against Nazi Germany.

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, Ukrainian SSR (Luhansk, Ukraine).

Later the series was renamed FDP (steam locomotive FD, passenger modification).