2-6-2

2-6-2 (Prairie)
Diagram of one small leading wheel, three large driving wheels joined together with a coupling rod, and one small trailing wheel

CGR 2nd Class of 1875, the first 2-6-2
Equivalent classifications
UIC class 1C1
French class 131
Turkish class 35
Swiss class 3/5
Russian class 1-3-1
First known tank engine version
First use 1875
Country Cape of Good Hope
Locomotive CGR 2nd Class 2-6-2TT
Railway Cape Government Railways
Designer Robert Stephenson and Company
Builder Robert Stephenson and Company
First known tender engine version
First use 1900
Country United States of America
Railway Chicago, Burlington and Quincy Railroad
Builder Brooks Locomotive Works
Evolved from 2-6-0
Drawbacks Nosing at speed

Under the Whyte notation for the classification of steam locomotives, 2-6-2 represents the wheel arrangement of two leading wheels, six coupled driving wheels and two trailing wheels. This arrangement is commonly called a Prairie.

Overview

The majority of American 2-6-2s were tender locomotives, but in Europe tank locomotives, described as 2-6-2T, were more common. The first 2-6-2 tender locomotives for a North American customer were built by Brooks Locomotive Works in 1900 for the Chicago, Burlington and Quincy Railroad, for use on the Midwestern prairies. The type was thus nicknamed the Prairie in North American practice. This name was often also used for British locomotives with this wheel arrangement.

As with the 2-10-2, the major problem with the 2-6-2 is that these engines have a symmetrical wheel layout, wherein the centre of gravity is almost over the centre driving wheel. The reciprocation rods, when working near the centre of gravity, induce severe side-to-side nosing which results in severe instability if unrestrained either by a long wheelbase or by the leading and trailing trucks. Though some engines, like the Chicago and Great Western of 1903, had the connecting rod aligned onto the third driver, most examples were powered via the second driver and were prone to the nosing problem.[1]

Usage

Australia

In Australia, no tender versions of the 2-6-2 operated on any system. However, three classes of 2-6-2T did.

In New South Wales a class of twenty engines, the Class 26, entered service in 1892 and operated until the end of steam. Two are preserved, no. 2606 at the Rail Transport Museum at Thirlmere and no. 2605 at the State Mine Museum in Lithgow.

The Silverton Tramway operated two 2-6-2T locomotives from 1891, both of which are preserved in South Australia.

The principal 2-6-2T locomotives which were built for the narrow gauge system of the Victoria Railway (VR), are the now famous "Puffing Billy" engines. Two of these little locomotives arrived from Baldwin Locomotive works in 1898 and a total of seventeen saw service throughout the state on the various narrow gauge timber and gold lines, including the Wangaratta and Walhalla. When the VR determined to close the Upper Ferntree Gully to Gembrook narrow gauge route in the mid-1950s, the Victorian community refused to let the train die. Today, the Puffing Billy Railway has a fleet of saved and modified 2-6-2T engines on active steam roster and is one of Victoria's main tourist attractions.[2]

Hungary

Standard Hungarian Railways 2-6-2 of 324 class, introduced in 1909

The most numerous steam locomotive type used in Hungary was the 324 class 2-6-2, built from 1909 onwards, which were still at work in the last days of steam.

The Hungarian State Railways (MÁV) also ran three important classes of 2-6-2 tank engines. These were the large 342 class built from 1917, and the smaller 375 class and 376 class.

New Zealand

A fleet of five tank engines, built by Manning Wardle of Leeds in England, were supplied to New Zealand in 1884-85. The private Wellington and Manawatu Railway (WMR) used them for construction, maintenance and local service work. Three were later taken over as the New Zealand Railways (NZR) WH class in 1908.

The second batch of Prairie locomotives was built to an order for the New Zealand Railways Department, with the initial order for ten being let to Nasmyth, Wilson and Company of Manchester, England. This later became the NZR V class which, due to political interference and their being overweight, did not go into traffic until 1890.

New Zealand's third batch of Prairie locomotives was ordered by the WMR in 1884. Their design was almost identical to that of the NZR V class, though they were slightly heavier. They could burn any light fuel, coal or wood as available, and entered service in 1886, soon after the WMR started operating. In 1908, with the purchase of the company by the NZR, they were also awarded the V classification.

NZR N class prior to its NZR service, as No. 9 of the Wellington and Manawatu Railway, at Paekakariki

In 1885, Baldwin Locomotive Works built New Zealand's fourth batch of Prairie locomotives. These were to become the NZR N class. Six were delivered in 1885 and were of an almost identical design to the previous, but altered to utilise off-the-shelf components supplied by Baldwin. In 1901, four more were built for the NZR, but these were fitted with piston valves actuated by Walschaerts valve gear. In 1891, two of these locomotives had also been built to the same design for the WMR. In 1908, with the purchase of the WMR by NZR, all of these engines were classified as N class.

Between 1894 and 1904, four similar engines were built by Baldwin for the WMR. In 1908, these became the NZR’s NA class and NC class, with two units each.

The NZR’s Addington Workshops joined the list of Prairie suppliers in 1889, producing the first of two NZR W class tank engines. These were followed between 1892 and 1901 with eleven similar NZR WA class tank engines.

Baldwin followed this up with ten similar NZR WB class Prairie tank engines in 1898.

In 1930-31, after nearly thirty years of 4-6-2 Pacific and 4-6-4 Baltic locomotive production, New Zealand dusted off its Prairie plans with the release into service of twenty-four NZR C class 2-6-2 locomotives, designed primarily for shunting and branch line work.

Poland

PKP Class Ol49 at work in summer 1976

The H. Cegielski Metal Works in Poznań produced 122 OKl27 class 2-6-2T locomotives for the Polish State Railways (PKP) during the period between 1928 and 1933.

Between 1951 and 1954, Fablok built a series of 116 Ol49 class 2-6-2 tender locomotives for the PKP.

Romania

Romania designed the 131.000 Class to replace the older Hungarian MAV locomotives used on Căile Ferate Române (CFR) secondary lines. A total of 67 locomotives were built at Reşiţa Works between 1939 and 1942, numbered 131.001 to 131.067.[3]

Russia & Soviet Union

Russian S-series 1-3-1

In Russia, the 2-6-2 was the standard passenger locomotive. They were represented by the pre-revolutionary S (С) (Sormovskij) series and the post-revolutionary Su (Су) series locomotives, the latter of which appeared in 1928. The pre-revolutionary S-series locomotives had the characteristic pointed nose, absent on the Su locomotive. The suffix 'u' means 'usilenny' which translates as strengthened or uprated. Several Su-series locomotives are preserved in working order. However, only one pre-revolutionary S-series locomotive is still around, number S.68. It is preserved at the Saint Petersburg railway museum.

Su 206-56 in steam at the Lebyazhye Railway Museum, Lebyazhye, Lomonosovsky District, Leningrad Oblast, Russia

The Su was the standard passenger engine on most mainline routes and it was only on the key trunk lines that the IS class 2-8-4, or later the P36 4-8-4, would be used. Therefore, the majority of passenger miles were hauled by an Su (Су).

Visually, the Su was the last true Russian-look design before the American influence of high running boards, bar frames and boxpok wheels became the norm. The Su retained such features as a clerestory skylight in the cab roof and handrails on the outside of the running board. These handrails were a result of the harsh Russian winters, when ice would build up on the running boards, making them highly dangerous. Enginemen had fallen to their death from moving trains and the fitting of promenade deck style handrails was a safety measure ordered by the Tsar in pre-revolutionary times. These features, combined with the high 17 feet (5.182 metres) loading gauge, combined to give the locomotives a uniquely Russian appearance.[4][5]

South Africa

The world's first 2-6-2 Prairie type locomotives were also the first locomotives to enter service on the new Cape gauge mainline of the Cape Government Railways. They were 2-6-2 side-tank engines that were delivered between 1875 and 1879. Four-wheeled tenders were also acquired on a subsequent order and the locomotives could be operated in either a tank or tank-and-tender configuration, as circumstances demanded. These locomotives were later designated the Cape 2nd Class.[6]

Zululand Railway Co. no. 1, c. 1901

In 1901, the Zululand Railway Company, contracted for the construction of the Natal North Coast line from Verulam to the Tugela River, acquired one 2-6-2 side-tank locomotive as construction engine from Baldwin Locomotive Works. Upon completion of the line in 1903, the locomotive was taken onto the roster of the Natal Government Railways and was designated Class I.[6]

CGR 6th Class, SAR Class 6Y

The first four Prairie locomotives built for the Cape Government Railways (CGR) by Neilson, Reid and Company, later designated Class 6Z on the South African Railways (SAR), were placed in service in 1901, but they displayed the Prairie’s tendency to be unsteady at speed. They were therefore soon modified to a 2-6-4 Adriatic wheel arrangement.[6]

With an improved design of bissel truck, two more CGR locomotives which were ordered from Kitson and Company in 1903 were once again built with a 2-6-2 Prairie wheel arrangement. These two locomotives did not display the tendency to sway at speed and therefore retained their 2-6-2 wheel arrangement. In 1912, when they were assimilated into the SAR, they were renumbered and designated Class 6Y.[6][7]

Switzerland

Tank locomotive BT Eb 3/5 no. 9 of the Dampf-Loki-Club Herisau

Switzerland had four classes of 2-6-2 tank locomotives.

Mostindien-Express with tank locomotive Ec 3/5 no. 3 of the Verein Historische Mittel-Thurgau-Bahn

In 1997, the MThB no. 3 was used as the prototype for the locomotive in the animated 20th Century Fox motion picture Anastasia, where it was given the appearance of a Soviet Union continental locomotive numbered 2747.

United Kingdom

Standard gauge

London and North Eastern Railway V2 class 60800 Green Arrow

The first United Kingdom 2-6-2 tender locomotive was the unsuccessful prototype Midland Railway Paget locomotive of 1908.[13] Thereafter, the wheel arrangement was rare on tender locomotives, with the exception of two classes on the London and North Eastern Railway. These were the Class V2 and Class V4 mixed traffic locomotives which totalled 186 locomotives between them.[14]

In contrast, 2-6-2T locomotives were very widely used on suburban passenger services, particularly by the Great Western Railway (GWR), who built four main classes between 1903 and 1947. (See GWR 2-6-2T).

Sir Henry Fowler of the London Midland and Scottish Railway (LMS) introduced a successful 2-6-2T class in 1930, which became the basis of further similar classes by Stanier in 1935 and Ivatt in 1946.

Sir Nigel Gresley of the London and North Eastern Railway (LNER) introduced his V1 and V3 classes in 1930.

The last new 2-6-2T locomotives in Britain were the British Railways standard class 2, built between 1953 and 1957. The design derived from the earlier LMS Ivatt Class 2 2-6-2T.

Narrow gauge

Vale of Rheidol Railway 2-6-2T No. 7 Owain Glyndŵr at Aberystwyth

The 2-6-2T layout was popular for large narrow gauge engines, but the design was modified to allow the use of a firebox much wider than the track gauge. A standard gauge 2-6-2T normally has inside frames and the firebox is placed between the second and third coupled axles. A narrow gauge one, on the other hand, has outside frames and the firebox is placed behind the third coupled axle and clear of the wheels. To minimise the rear overhang, the fuel is therefore carried in side-bunkers alongside the firebox, instead of in a rear bunker.

Preserved examples include the Welsh Highland Railway's Russell and the Vale of Rheidol Railway locomotives.

United States of America

Narrow gauge

Baldwin 2-6-2T no. 104 steaming out of Hill City, South Dakota, on the Black Hills Central Railroad in 2001

The 2 ft (610 mm) gauge Sandy River and Rangeley Lakes Railroad in Franklin County, Maine, was a major narrow gauge 2-6-2 user.

Standard gauge

In the United States, the type evolved from the 2-6-0 configuration. The Atchison, Topeka and Santa Fe Railway (AT&SF) became a pioneer of the type in the United States in 1901 and one of the largest fleet users of the type. Problems the road encountered with the type included steam leakage in the compound cylinder plumbing and instability at speed. The former problem was solved by converting them to simplex two-cylinder locomotives; the latter problem required new Pacific types with four-wheeled guide trucks. The Prairie types were rebuilt with smaller drivers for slightly slower fast freight service. These engines tended to enjoy very long service lives, and outlasted many a newer, more efficient steam locomotive on the Santa Fe and elsewhere. This was due to their modest weight, good speed and ability to operate well in reverse, which made them valuable for branch line operations.

A Prairie type built for the Burlington by Baldwin

In 1902, the AT&SF had a 2-6-2 with a high, at the time, boiler pressure of 220 pounds per square inch (1,517 kilopascals), mounted on a large 41 square feet (3.8 square meters) fire grate.[1]

More than a thousand examples of the 2-6-2 wheel arrangement existed in the United States. Of these, one hundred were high-wheeled engines with larger than 69 inches (1,753 millimeters) drivers. The Lake Shore & Michigan Southern operated locomotives with 80 inches (2,032 millimeters) drivers, but this did not overcome their inherent instability. They were never as successful in passenger service in the U.S. as they were in other nations.[1]

References

Wikimedia Commons has media related to 2-6-2.
  1. 1 2 3 Swengel, F.M. The American Steam Locomotive, Vol. 1, The Evolution of the Steam Locomotive, MidWest Rail Publications, Davenport, 1967. pp. 78-80.
  2. Oberg, Leon. Railways of Australia, Reed, Sydney, 1975. (plus subsequent editions)
  3. 131.000 Class Locomotive at railwayfan.ro (Romanian)
  4. Russian Steam Locomotives, LeFleming/Price
  5. Locomotives of Russia 1845 - 1955, V.A.Rakov
  6. 1 2 3 4 Holland, D.F. (1971). Steam Locomotives of the South African Railways, Volume 1: 1859-1910 (1st ed.). Newton Abbott, Devon: David & Charles. pp. 23–25, 52–54, 56, 90–91. ISBN 978-0-7153-5382-0.
  7. Paxton, Leith; Bourne, David (1985). Locomotives of the South African Railways (1st ed.). Cape Town: Struik. p. 45. ISBN 0869772112.
  8. http://bt9.ch/index.php?article_id=12
  9. http://www.dbb.ch/
  10. http://www.dampfgruppe-zuerich.ch/index.php/fahrzeuge/eb-3-5-5811-habersack/geschichte-habersack
  11. http://www.sbbhistoric.ch/de/sammlungen/fahrzeuge/lokomotiven/dampf/eb35-5819.html
  12. http://www.mthb.ch/rollmaterial/mostindien-express.html
  13. Boddy et al. 1984, p. 69
  14. Boddy, M. G.; Brown, W. A.; Hennigan, W.; Hoole, Ken; Neve, E.; Yeadon, W. B. (September 1984). Fry, E. V., ed. Locomotives of the L.N.E.R., Part 6C: Tender Engines—Classes Q1 to Y10. Kenilworth: RCTS. ISBN 0-901115-55-X.
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