Russian State 2-6-2 Locomotives in Russia

Class S (Locobase 14199)

Data from Tomasz Galka, Standard Gauge Steam Locomotives at [], last accessed 28 May 2012, and diagram at [].

Galka traces development of this passenger engine to a turn-of-the-century requirement for larger., more powerful locomotives that could burn the local low-calorie fuel (brown coal or even wood). Apparently beginning with a large grate within a square-sided Belpaire firebox, the designers drafted a well-proportioned boiler with the trailing axle under the firebox. Although the front truck and leading driving axle were combined in a Zara-Krauss truck for better lateral play, the rear truck was rigidly mounted. Note that axle loading limits kept the weight down.

Satisfied with the trials of five prototypes turned out by the Sormovskii Zavod of Nizhny Novgorod in 1910, the railway ordered over 56 dozen from Kharkovskii, Luganskii, Nevskii, and Sormovskii over the next eight years. Galka neatly sums up the success of these engines: "Basically intended to haul fast and comparatively light trains, these engines hauled almost anything they could manage, fired with whatever was at hand."

Of the 678 originally produced, 655 still appeared on the Soviet NKPS (Ministry of Transport) rolls in 1942. Locobase thinks it unlikely that all were still in service, however. Significant withdrawals began in 1950 with the last being retired in 1964.

Given that only eleven of the original S class ever came to Poland (and ten of the eleven were immediately handed over to Latvia's Latvijas Dzelzcels (LDZ)), Galka's account of this class is a selfless contribution to the canon. A variant of the S for standard-gauge operation, the Sw, appears in Locobase 14200.

Class Sw (Locobase 14200)

Data from Tomasz Galka, Standard Gauge Steam Locomotives at [], last accessed 28 May 2012, and diagram at [].

Locobase 14199 describes the S class passenger Prairie engine developed by the Russian State Railways for its broad-gauge system. In 1913, the RSR ordered a small subset of the class to operate on the Warsaw-Vienna service on standard-gauge track.

The narrower frames and other loading-gauge considerations led to some changes. The boiler's centerline dropped by 150 mm (5.9") and its pressure setting was reduced by 1 bar; cylinder diameter increased by 25 mm to compensate. The lead truck, which carried both the lead idler and the first driving axle, was changed from the Zara-Krauss design to the more widely used Krauss-Helmholz (possibly in deference to maintenance requirements at the Vienna end of the line). The rear axle now enjoyed lateral play through a Bissel truck and the Westinghouse air-brake system was replaced by Hardy vacuum brakes.

Only 15 Sws were built in 1914-1915 and these were converted to broad-gauge operation after the Russians lost Warsaw. Post-war agreements to return the engines to Poland as the PKP's Ol101were not honored and the class remained in Soviet service until the late 1950s.