72xx class pulling freight train

History of the 7200 Class (72XX) Locomotives

The Great Western Railway (GWR) 7200 class was a class of 2‑8‑2T steam locomotive. They were an evolution of the earlier 4200 and 5205 class locomotives, and were the largest tank engines to run in Great Britain.

Background

7200 class locomotive in service

By 1910, the GWR was struggling against local competition (before grouping) to cope with the heavy loads of coal and the harsh topographical conditions of the valley branch lines of the South Wales coalfields. Although it had produced the successful 2800 class heavy freight locomotives, these were found to be unsuitable for working the branch lines, leaving the GWR to rely on vintage tank stock to carry out these tasks.

This situation required the Swindon office to create a new design that was capable of bringing the GWR's principal traffic of coal to the main line and the docks, together with iron ore to the local steelworks, in the most efficient and economical manner.

A specification was developed calling for a short haul tank engine with high tractive effort, the use of standard parts, and minimum running costs. A 2‑8‑2T locomotive had been conceived as one of G.J.Churchward's turn-of-the-century Standard Plan designs, to cover the whole of the GWR requirement for motive power into the foreseeable future; this design was rejected, however, because of its wheel base was considered too long.

4200 class (42XX)

  • Configuration: 2‑8‑0T
  • Driving Wheels: 4 ft 7.5 in
  • Boiler: Standard № 4
  • Cylinders: 18.5 in x 30 in (2)
  • Tank capacity: 1800 gallons
  • Bunker capacity: 3 tons
  • Weight: 81 tons 12 cwt
  • Tractive effort: 31,450 lbs

In 1910 a prototype 2‑8‑0T was built, number 4201, which shared a number of parts with the 2800 class heavy freight locomotives. It was a short-haul locomotive with excellent adhesion.

In 1912, after fourteen months of trials, the initial production batch of locomotives were built. These had flared bunkers to carry an extra half-ton of coal. The class proved such a success that production continued up to number 4299, then from 5200 to 5204 before number 4200 was built in February 1923.

5205 class (5205)

  • Configuration: 2‑8‑0T
  • Driving Wheels: 4 ft 7.5 in
  • Boiler: Standard № 4
  • Cylinders: 19 in x 30 in (2)
  • Tank capacity: 1800 gallons
  • Bunker capacity: 4 tons
  • Weight: 82 tons 2 cwt
  • Tractive effort: 33,170 lbs

After the 1923 grouping, Swindon inherited a large and variable collection of locomotives which did not fit into their standardisation programme. It was decided to replace some of these with an updated version of the 4200 class.

The first batch of 10 locomotives of the new 5205 class were fitted with larger cylinders (19in x 30in) and outside steam pipes, boosting their tractive effort to 33,170lbs. Between 1923 and 1926, 60 more examples were built, with minor detail alterations.

In 1930 a further batch of 20 locomotives 5275-94 was ordered to lot № 266. One noticeable change being the replacement of the austere looking running plate with the raised platform over the cylinders and the Holcroft curved drop ends.

Barely had the construction and running in of these locomotives begun (5275 completed 1408 miles during this period) when Britain was gripped in the great depression. The economic environment took a heavy toll on the coal and steel industry of South Wales, which prompted a reduction in motive power. It also meant that there was less urgency to replace the older, absorbed locomotives with new ones.

The situation created a great dilemma at Swindon: faced with the prospect of laying off skilled labour that would be lost forever to the railway industry, it was decided to continue the construction of this last batch of locomotives. They were completed and put into store at Swindon, allowing the 4200 class locomotives which they were to replace, and only being twenty years old, to continue in service.

7200 class (72XX)

  • Configuration: 2‑8‑2T
  • Driving Wheels: 4 ft 7.5 in
  • Boiler: Standard № 4
  • Cylinders: 19 in x 30 in (2)
  • Tank capacity: 2500 gallons
  • Bunker capacity: 6 tons
  • Weight: 92 tons 12 cwt
  • Tractive effort: 33,170 lbs

On 23rd July 1934, under the auspices of the Chief Mechanical Engineer Charles B.Collett, 5275 was taken out of storage, and entered the 'A' shop at Swindon. It was converted to the prototype of the 2‑8‑2T 7200 class, the final development of the GWR eight-coupled freight tank locomotive. The conversion included extending the frames by 4ft 1in, adding a radial truck with 3ft 8in diameter wheels; increasing the water capacity to 2500 gallons and the coal capacity to 6 tons. As a result, the locomotive weight increased to 92.6 tons.

The next 19 engines of the class were rebuilt from the remaining 5205 class engines in store. The greater coal and water capacity allowed the locomotives to operate the main line coal trains from South Wales to London, and to take heavy freight over the red routes to which they were restricted.

Because of the overall success of the 7200 class conversion, and an upsurge in coal and steel production, in 1935-36 another 20 5205 class locomotives were converted to 7200 class; numbers 5255-74 becoming numbers 7220-39.

In 1937, more rebuilds were ordered, taking the class size to 54. The locomotives used for this last batch of 14 were from the original 4200 class, and required a more extensive rebuild, including the fitment of new cylinders to the later 19 inch diameter standard. A decision was taken to slightly alter the coal and water capacities of this 7240-7253 batch, which became 5 tons and 2,700 gallons respectively. The locomotives used for these rebuilds were 4239, 4220, 4202, 4204, 4216, 4205, 4234, 4244, 4249, 4209, 4219, 4240, 4210 and 4245.

Withdrawal

The first 7200 class locomotive withdrawn was 7241 in November 1962 from Pontypool Road shed. The last four locomotives in the class were withdrawn together in June 1965: 7248 and 7249 from Llanelly shed; 7205 and 7252 from Severn Tunnel Junction shed.


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№ 7200

The life and times of № 7200.

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