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Soviet locomotive class ИС
Steam locomotive IS20-16 with streamline casing at the locomotive factory in Voroshilovgrad in 1937. It was the Soviet steam locomotive-champion with maximum speed of 155 km/h (96 mph).
Type and origin Power type Steam Builder October Revolution Locomotive Factory, Voroshilovgrad (Luhansk) Build date 1932–1942 Total produced 649
Specifications Configuration: ​  • Whyte 2-8-4 Gauge 1,524 mm (5 ft) Leading dia. 1,050 mm (41.34 in) Driver dia. 1,850 mm (72.83 in) Trailing dia. 1,050 mm (41.34 in) Adhesive weight 88 tonnes (87 long tons; 97 short tons) Loco weight 133 tonnes (131 long tons; 147 short tons) Firebox: ​  • Grate area 7.04 m2 (75.8 sq ft) Boiler pressure 15 kgf/cm2 (1.47 MPa; 213 psi) Heating surface 295.2 m2 (3,178 sq ft) Superheater: ​  • Heating area 148.4 m2 (1,597 sq ft) Cylinders Two, outside Cylinder size 670 mm × 770 mm (26.38 in × 30.31 in)
Performance figures Maximum speed 115 km/h (71 mph) Tractive effort 233.5 kN (52,490 lbf)
Career Numbers IS20-1 Retired 1965–1987 Scrapped 1975–1996

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 contract design was prepared in 1929 at V.V. Kuybyshev Locomotive Factory in Kolomna, Russian SFSR. The IS series locomotives were manufactured between 1932 and 1942. The last one was built in 1942 during the Great Patriotic War against Nazi Germany.

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, Ukrainian SSR (Luhansk, Ukraine). In total, 649 IS steam locomotives were constructed. Later the series was renamed FD^P (steam locomotive FD, passenger modification).

These locomotives were used until 1972.

• 
  IS20-1 in 1932
• 
  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 Kyiv

• The Museum of the Moscow Railway, at Paveletsky Rail Terminal, Moscow
• Rizhsky Rail Terminal, Home of the Moscow Railway Museum
• Russian Railway Museum, St.Petersburg
• Finland Station, St.Petersburg
• History of rail transport in Russia

• Главное управление локомотивного хозяйства МПС (1956). Справочник по локомотивам железных дорог СССР (in Russian). Трансжелдориздат.
• Сыромятникова, С.П., ed. (1937). Курс паровозов. Устройство и работа паровозов и техника их ремонта (in Russian). Трансжелдориздат (State Publishing House).

Wikimedia Commons has media related to Soviet locomotive class ИС.

• The Moscow Railway Museum at Rizhsky Rail Terminal