BR standard class 4 tank
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 80152 at Nine Elms MPD, 1965. |
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| Power type | Steam |
|---|---|
| Designer | R. A. Riddles |
| Builder | Brighton/Derby/Doncaster Works |
| Build date | 1951-1956 |
| Total production | 155 |
| Configuration | 2-6-4T |
| Gauge | 4' 8½" |
| Driver size | 5' 8" |
| Locomotive weight | 88 tons 10 cwt |
| Fuel type | coal |
| Boiler pressure | 225 psi |
| Cylinders | two outside |
| Cylinder size | 18" x 28" |
| Tractive effort | 25,100 |
| Class | 4MT |
The British Railways Standard Class 4 tank was a class of steam locomotive, one of the BR standard classes built during the 1950s. They were used primarily on commuter and outer suburban services.
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[edit] Background
On the nationalisation of British Railways (BR) in 1948 the London Midland Region had a number of ex-London, Midland and Scottish Railway 2-6-4T and the Western Region a number of "GWR large prairie" 2-6-2T types. These tank engines were particularly suited to commuter and secondary services. However, particularly in Scotland and the Southern Region, the situation was not so good with large numbers of pre-grouping types struggling on.
[edit] Design and construction
On the decision to build the BR standards, a series of class four tank engines was ordered, based on the ex-LMS Fairburn 2-6-4T with some modifications. The Fairburn tanks themselves had been based on the LMS Stanier 2-6-4T which in turn had been based on the LMS Fowler 2-6-4T.
Design work was done at Brighton, the overall programme being overseen by R.A. Riddles. The principal modifications to the Fairburn design involved the reduction of their envelope to enable them to fit into the L1 loading gauge. To do this, the tanks and cab were made more curved than the Fairburn design, the Fairburn having a straight-sided tank. The biggest mechanical change was a reduction in cylinder size, also to reduce cross-section, and a corresponding increase in boiler pressure to compensate. Other visible changes include the reintroduction of a fall plate.
Most of the class of 155 were built at Brighton, 15 (80000-9/54-8) at Derby and 10 (80106-15) at Doncaster between 1951 and 1956. The first to emerge was 80010 from Brighton in 1951. Fifteen that were due to be constructed in 1957 were cancelled due to impending dieselisation, and the last five would have been too had they not been in an advanced stage of construction when the order came to cancel them.
The BR standard class 4 4-6-0 was essentially a tender engine derivative of the Standard Class 4 tank.
No significant modifications were made to the design. The tank vent was found to restrict the driver's vision and was moved further forward from 80059. Initially built with fluted coupling rods, these caused problems on other classes and from 80079 plain section coupling rods were substituted.
[edit] Service
The standard four tanks were allocated to all regions apart from the Western Region. They became particularly associated with the London, Tilbury and Southend Line working commuter services out of London until that was electrified in 1962. They were then gradually displaced to further-flung regions.
[edit] Withdrawal
In the 1960s there was a mass withdrawal of steam types. Older types were withdrawn in preference to the Standard Fours which all remained intact until 1964 (apart from one written off in a collision). The final nine were withdrawn from the Southern Region on 9 July 1967. One Scottish Region example, 80002, remained in Glasgow past the end of steam haulage until 1969 on carriage heating duties.
[edit] Preservation
No fewer than fifteen Standard Four tanks have survived the cutter's torch. These are:
| Number | Home | Notes | Link to UK preserved loco database |
|---|---|---|---|
| 80002 | Keighley and Worth Valley Railway | Fully operational | database |
| 80064 | Bluebell Railway | Currently on static display in shed | database |
| 80072 | Llangollen Railway | Currently under restoration | database |
| 80078 | Swanage Railway | Locomotive away at South Devon Railway for contracted repairs | database |
| 80079 | Severn Valley Railway | Cosmetically restored in The Engine House. | database |
| 80080 | Midland Railway Centre | Currently under overhaul in the West Shed at Swanwick Junction. | database |
| 80097 | East Lancashire Railway | Currently under restoration | database |
| 80098 | Midland Railway Centre | Currently on loan to the Churnet Valley Railway. | database |
| 80100 | Bluebell Railway | Awaiting restoration. | database |
| 80104 | Swanage Railway | Valve Liners found defective during Valve and piston examination. | database |
| 80105 | Bo'ness and Kinneil Railway | Operational. | database |
| 80135 | North York Moors Railway | Only Class 4MT preserved in British Rail green livery. No 4MTs ran in British Rail green whilst in mainline service. Recently withdrawn from service, awaiting a full overhaul. | database |
| 80136 | Llangollen Railway | Current boiler ticket expired | database |
| 80150 | Barry Island Railway | Still as recovered from scrapyard | database |
| 80151 | Bluebell Railway | In regular use. Boiler ticket expires in 2011. | database |
[edit] References
- A Detailed History of British Railways Standard Steam Locomotives: vol 3 Tank Engine Classes Paul J Chancellor, R K Taylor (Editor), (December 1997) Railway Correspondence & Travel Society (RCTS) ISBN 0-901115-77-0
[edit] External links
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