Following the success of the prototype "Large Prairie" tank locomotive (see loco 5199, which visited us in 2008) a prototype "Small Prairie" tank was built by the Great Western Railway in 1904; "Prairie" denotes the 2-6-2 wheel arrangement. This prototype loco, which was intended for service on branch lines in the West Country and Wales, was developed into the 4500 class 2-6-2T. The 4575 class (of which 100 were built, numbered 4575-4599 and 5500-5574) is similar to the 4500 class but has larger, sloping side water tanks.
No.5521 was built at the GWR's Swindon Locomotive Works as part of lot number 249 (Locomotive Nos.5505-5524) and was completed in December 1927. Its initial allocation was Newton Abbot shed. At Nationalisation it was allocated to Taunton (83B), where it remained until June 1951, moving to Machynlleth (89C) until November that year. Returning to the West Country No.5521 was shedded at St. Blazey (83E) until August 1958, when it returned to Taunton (83B). Its final BR shed was Laira (83D) from November 1961 until withdrawal in April 1962, after having run just over a million miles. The last four locomotives of the class were withdrawn in December 1964.
The photo on the right shows L.150 being delivered to Sheffield Park in December 2013. Note the Westinghouse air pump, the cabside shutters which were added to comply with wartime "blackout" requirements, and the raised section at the rear of the bunker which protects the top lamp from falling coal. (John Sandys)
No.5521 was sold for scrap to Woodham Bros. at Barry and languished in Woodham's yard until it was sold for preservation to the Dean Forest Railway in late 1975. It was purchased by Richard and William Parker in 1980 and was finally restored at The Flour Mill in the Forest of Dean between 2004 and 2007. The locomotive is largely as built, but with the addition of a Westinghouse air pump on the driver's side, giving No.5521 the ability to brake trains fitted with either vacuum or air brake.
In April 2007 No.5521 went by sea from Hull to Gdynia in Poland, via Helsinki, and featured in the Wolsztyn Parades of 2007/8/9. It also undertook main line workings in Hungary and Slovakia, plus suburban services from Wroclaw (Poland). In 2009 it returned to England and has since visited the National Railway Museum and several heritage railways.
In May 2013, at the request of London Underground, the locomotive was painted in red London Transport livery (similar to that worn by the ex-GWR pannier tanks used by LT until 1971) and numbered L.150, to commemorate the 150th anniversary of the Metropolitan Line. The loco has since operated special trains on LU and visited a couple of other locations in addition to its hire to the Bluebell Railway.
This photo, showing No.5521 at Didcot on 4 May 2010, is by Tony Hisgett of Birmingham.
It is reproduced here, cropped and scaled, under Creative Commons Attribution 2.0 Generic licence.
Cylinders: (2) 17 x 24 inches
Driving wheel diameter: 4 feet 7 1/2 inches
Bogie/trailing wheel diameter: 3 feet 2 in
Tractive effort: 21,250 lbs
Boiler type: GWR No.5
Fire tubes, no. and diameter: 196 x 1 5/8 inches
Flue tubes, no. and diameter: 6 x 5 1/8 inches
Superheater tubes, no. and diameter: 36 x 1 inch
Boiler pressure: 200 lbs/square inch
Area of firegrate: 16.6 square feet
Heating surface, tubes: 992.51 square feet
Heating surface, firebox: 94.25 square feet
Heating surface, superheater: 73.8 square feet
Length of loco: 36 feet 4 1/2 inches over buffers
Total weight: 61 tons 0 cwt
Water capacity: 1,300 gallons
Coal capacity: 3 tons 14 cwt
G.W. power class: C
Route availability: Yellow
BR power classification: 4MT
Cameron Smith's photo shows L.150 approaching Three Arch Bridge, with the Bluebell's matching Metropolitan Railway stock and some SR Maunsell stock, on 21 August 2013.
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