2-10-0

Under the Whyte notation for the classification of steam locomotives, a 2-10-0 is a locomotive with two leading wheels, generally in a radially swinging leading truck, and ten coupled driving wheels, five on each side. This arrangement was often named Decapod, especially in the United States, although this name was sometimes applied to locomotives of 0-10-0 "Ten-Coupled" arrangement.

Other equivalent classifications are:

*UIC classification: 1E (also known as German classification and Italian classification)
*French classification: 150
*Turkish classification: 56
*Swiss classification: 5/6

These locomotives were popular in Europe, particularly in Germany, and in Russia; British use of the type was confined to the period during and after World War II. In the United States, the 2-10-0 was not popular but was a favorite of a small number of railroads, mostly in mountainous terrain.

The 2-10-0's main advantage was that five out of six of its axles were powered, meaning almost all the weight was available for traction rather than being distributed over pilot and trailing wheels. The long rigid wheelbase caused problems on tightly curved track, so blind drivers were the norm, either on the central axle, and/or on the second and/or fourth axles. Often lateral motion devices were attached to the leading drive axle.

The wheel arrangement's disadvantages included the firebox size restriction caused by the lack of trailing wheel. This meant the firebox was fitted in between the wheels (common on earlier locomotives) and was long and narrow, or if mounted above the driving wheels, was wide and long but shallow. Many locomotives chose the latter option. A firebox mounted over the drivers also restricted the diameter of the driving wheels, which in turn limited speed. As with the consolidation (2-8-0), "chopping" at speed ensured a rough ride for the crew due to instability caused by the wheel arrangement. In fact, backing any locomotive without a trailing axel was restricted to under twenty miles per hour or less. Most 2-10-0s were not operated at speeds greater than 50 mph (80 km/h).

The type operated as freight engine, although locomotives in Germany and the United Kingdom proved capable of hauling passenger trains.

United States

The first Decapods built for the Lehigh Valley Railroad in 1867 proved too rough on the track because of their long coupled wheelbase, so one pair of drivers were removed.Fact|date=February 2007 No more followed for 24 years, until the Erie Railroad bought six for pusher service between 1891 and 1893. In low-speed service where high tractive effort was critical, these Decapods were successful. Small numbers of other Decapods were built over the next twenty years, mostly for service in steeply graded mountainous areas where power at low speeds was the requirement. The type did not prove as popular as the successful Consolidation (2-8-0) type. Among Decapod users was the Santa Fe Railway. The engines were tandem compounds but their ongoing reversing limitations became the genesis of the 2-10-2 wheel arrangement.

The first boost in the number of Decapods occurred when Imperial Russia ordered approximately 1200 Decapods from American builders during World War I. When the Bolshevik revolution occurred in 1917, over 800 had already been delivered, but more than 200 were either awaiting shipment or were in the process of construction.Fact|date=February 2007 These stranded locomotives were adopted by the United States Railroad Administration (USRA), the body created by the Government to oversee and control the railroads during the War, converted to American standards, and put to use on American railroads. Small and light-footed, these Russian decapods proved popular with smaller railroads, and many of them remained in service long after the USRA's control of the railroads ceased. Many indeed lasted until the end of steam on those railroads.

Swengel suggested the 2-10-0 arrangement was 'obsolete' by 1916, when the Pennsylvania Railroad (PRR) commenced an experiment with a 2-10-0 locomotive at its Juniata plant. [Swengel, pp.190-191.] Most 10 coupled engines constructed for U.S. railroads during World War 1 were of the USRA 2-10-2 arrangement, but the PRR committed to 122 of the 2-10-0s. [Swengel; Staufer, p.65.] Swengel argued this commitment to the 2-10-0, nicknamed "Deks", was controversial even in 1916, but it was even more so in 1922 when the PRR placed additional orders. The PRR was soon the biggest user of Decapods in the United States. The type was ideally suited to the Pennsy's heavily graded Allegheny Mountains routes, which required lugging ability according to tractive effort, not speed according to horse power.

The PRR bought 598 2-10-0s including 123 built at its own shops. In one of the largest locomotive orders ever, the rest came from the Baldwin Locomotive Works. The PRR 2-10-0s weighed 386,100 lb (175.1 t) and developed 94,024 lbf (418.2 kN) of tractive effort with an axle loading of over 70,000 lb (32,000 kg). The engines steamed at 250 psi (1.72 MPa) and had a relatively large superheater. The grate area of about 70 sq ft (6.5 m²) was on the small side, but a mechanical stoker partly compensated for this.Swengel.] The debate about whether the PRR's 2-10-0s were the best of their kind, predicted Swengel, "must remain a great unknown."

The PRR decapod, class I1s, was unlike the Russian decapod; it was huge, taking advantage of the PRR's heavy trackage and high axle loading, with a fat, free-steaming boiler that earned the type the nickname of 'Hippos' on the PRR. Two giant cylinders (30½ x 32 inch) gave the I1s power and their giant tenders permitted hard and long workings between stops. They were unpopular with the crews, for they were hard riding.Staufer] Indeed, one author described them as the holy terror of the PRR.Fact|date=February 2007 The last operations on the PRR were 1957.

A small number of other Decapods were ordered by other railroads; those built for the Western Maryland Railroad were the largest ever built, at almost 420,000 lb (190,500 kg) weight. A small short line railroad, the Durham and Southern Railway, bought a few new Decapods from Baldwin. Nos. 200-201 were bought in May 1930 and No. 202 was purchased in September 1933.Fact|date=February 2007

Thirteen Decapod locomotives survive in the USA, including six Russian Decapods and one PRR I1s. Two, including one Russian decapod at the Illinois Railway Museum, are operational.

Germany

The 2-10-0 arrangement was a very popular one in Germany. The first were built by the individual state railways from 1915 to 1918, and these later became the DRG BR58. The DRG then produced a number of standard classes of 2-10-0s: the heavy 3-cylinder BR44 (1753 built), the two-cylinder version BR43 (35 built), and the lightweight BR50 (3164 built). During wartime, the BR44 and BR50 designs were simplified as ÜK ("Übergangs Kriegslokomotiven", or interim war locomotives). By 1941, it was clear that even these were too complicated, expensive, time-consuming to build, and used too much of materials in short supply, so new "Kriegslokomotive" (war locomotive) designs were developed; the lightweight BR52 (6161 built) and the intermediate weight BR42 (844 built).

Postwar locomotives of these types, particularly the BR 52, were spread all over Europe and were taken into service by the railways of many different countries:
* BR44 in France, SNCF 150X.
* BR50 in Belgium, NMBS/SNCB class 25; in Denmark, DSB class N.
* BR52 in Austria, ÖBB class 52; in Belgium, NMBS/SNCB class 26; in Norway, NSB class 63.

United Kingdom

Locomotives with ten driving wheels were rare in British railway history. The first 2-10-0 was built during the Second World War, as a variant of the "Austerity" 2-8-0 for lightly built railways. The only other 2-10-0 type was the 251 strong Class 9F introduced by British Railways in the 1950s. It included 92220 "Evening Star", the last steam locomotive built by British Railways, in 1960.

Finland

The State Railroads of Finland purchased 20 American Decapods after WWII - these were originally built for the Soviet Union, but never delivered to them. Of the 20 engines, 10 were made by Baldwin, 10 by ALCO. Since they were originally built for the USSR, they had the correct gauge for Finland, too (1524 mm/5 ft. exactly). One (ALCO # 75214, 1947) is preserved at the Finnish Railway Museum in Hyvinkää, Finland.

France

From 1910 to 1951, the French industry built more than 500 decapods for three railway companies (Paris-Orléans, Nord, Est) and for the national railways (SNCF). Moreover, at the end of World War II, SNCF inherited more than 200 units of German decapods built in France, mostly BR 44. The last decapod, a SNCF 150P, was withdrawn in 1968. All 2-10-0s, of French or of German design, proved reliable and powerful in service. One can notice that some engines of the Paris-Orléans company were dedicated to passenger service on difficult mountain lines.

Soviet Union

2-10-0 were fairly common freight locomotives in the former Soviet Union. They came from several sources: US imports (series Ea and Eb, built by ALCO and Baldwin, respectively), German war trophy BR52 class locomotives and locally built. The locally built 2-10-0 locomotives were represented by SO (Sergo Ordjonikidze) and L (Lebedyanski)–series locomotives. The L-series locomotives were one of the more advanced steam locomotives built in the former Soviet Union. They used stocker to feed coal and had a relatively low axle load (18 tonnes or 40,000 lb) to be compatible with the war-torn railroads of the former Soviet Union. Several examples of these locomotives are still preserved in working order.

References

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External links

* [http://www.irm.org/cgi-bin/rsearch.cgi?steam=St.+Louis-San+Francisco+Railroad=1630 Illinois Railway Museum's roster page for SLSF 1630 (the operable 2-10-0)]