An unknown Nw, photographed probably somewhere in Russia, date unknown. Source: www.en.wikipedia.org. Class NW had larger drivers, but was otherwise very similar externally.
Locomotive As-56 (later re-classed Nu), photographed in Nizhny Novgorod in 1911. Source: www.commons.wikimedia.org.
In 1892 Aleksandrovskiy Zavod built two prototype 1-3-0 passenger locomotives with 1900 mm drivers. Designed by Nikolai Shchukin with the assistance of Belgian engineer Alfred Belpaire, these engines were originally intended to replace earlier class K (2-2-0) and avoid double-heading with heavier passenger trains. Following positive experience with class O freighters, it was decided to use compound steam engine. Although axle load turned out to be higher than expected by almost two tonnes, new locomotive was finally accepted and classed N (H in Russian script). According to some sources this designation came from the Nikolaevskaya railway that placed first orders. In fact at this time all railways, state-owned and private, had their own numbering schemes. In 1912, after unification had been introduced, this designation was retained as this was the first vacant letter in the Russian alphabet.
First variant featured Joy valve gear, hence after 1912 it was re-designated ND (HД); production totaled 127 examples. NW (HB, upper case superscript) had Walschaert gear and Bissel pony truck instead of the Adams axle. It was built in 167 examples, all for government railways. Nw (Hb, lower case superscript) featured 1700 mm drivers, sacrificing speed for tractive effort; it was the most numerous sub-type, 589 engines being built between 1903 and 1911. Nu (Hy) was the ‘strengthened’ version with modified boiler and low-pressure cylinder bore increased to 750 mm. It appeared in 1910 and was built in 121 examples. There were nine more sub-types, most with 1700 mm drivers, built in much smaller numbers; some were fitted with single-expansion steam engines and steam superheaters, the latter being distinguished by subscript or superscript P, or П in Russian script. Total output was 1083 examples, built by all major Russian locomotive manufacturers, apart from six delivered by German Union works. The latter, classed NR (HP), ran on saturated steam, featured 1800 mm drivers and single-expansion steam engines; due to poor economy this version was not ordered in quantity. After WWI all remaining engines of this type were converted to singles and fitted with superheaters. Last survived in service until 1950s, but not a single example has been preserved.
According to LP, after WWI Polish railways obtained seven locomotives of this type. Their numbers are not known, nor is to which sub-types they belonged. Locomotive specifications list published by the Ministry of Transport in 1927 (see references) lists just one, which had been renumbered Oi102-1. This engine is of the NW sub-type and its year of manufacture is given as 1904. If this is correct, it might have been built by Luganskiy Zavod or Sormovskiy Zavod, which in 1904 delivered six and fifteen examples, respectively, to railways in the area which became part of Poland in 1918 – but this is just a conjecture. Oi102-1 disappeared from the PKP rosters before 1936 and most probably was scrapped. All remaining engines of this type were probably not re-designated and written off before 1926.
Main technical data
Note: all data except total built refer to the NW version.
1) NW version.
References and acknowledgments
- LOZD vol.1;
- Charakterystyka parowozów (Steam Engine Specifications) by A.Czeczott (Ministry of Transport, 1927)