History File - A History of Our 57xx Pannier Tank Family— Accurascale Léim ar ábhar
History File - A History of Our 57xx Pannier Tank Family

History File - A History of Our 57xx Pannier Tank Family

Curious about Pannier tanks? Join our Project Manager Steve Purves as he takes us on a journey through the interesting and extensive history of these charismatic work horses!


The pannier tank story starts in the early part of the 1900s when the Great Western Railway started to replace the round topped fireboxes on some of its older locomotives with more efficient Belpaire fireboxes. The Belpaire firebox is a square design and gives improved heat transfer from the fire to the water in the boiler however fitting a saddle tank over the top of such a design would prove unnecessarily difficult.

Other railways had adopted side tanks in place of earlier saddle tanks, the tanks extending all the way down to the footplate. This is great for stability and water capacity but not so good when it comes to servicing the inside workings of a steam locomotive. The pannier tank was deemed to be a better all round decision and this was adopted as standard for almost all GWR 0-6-0 locomotives going forward. Rebuilds continued various elderly classes of locomotive right up to (and past) the grouping in 1923, this grouping brought a vast array of different designs of locomotive from 28 acquired companies. This created a nightmare for maintenance, crew training and rostering. A standard locomotive would be the answer.

Concept and Early Orders

What was required was a standard, go-anywhere lightweight yet powerful tank locomotive. One that everyone could be familiar with that’s easy to maintain and handle. The design drew from many now standard GWR features, Belpaire boiler, inside cylinders driven by Stephenson’s valve gear, enclosed cab and most notably, pannier tanks. From the design office of Charles B Collett, 100 locomotives were ordered, these were developed from the earlier rebuilt 2721 class and were designated the 5700 class. Of the first hundred locomotives, fifty were built by the North British Locomotive Company in Glasgow (at both Hyde Park and Queens Park works) and fifty were built in the Great Westerns own workshops in Swindon.

Almost immediately a further 200 locomotives were ordered, funded for by the British government as part of a work creation scheme. They 200 locomotives were split between 6 contractors: North British (50), Bagnall (50), Beyer-Peacock (25), Kerr-Stuart (25), Armstrong Whitworth (25) and Yorkshire Engine Co. (25).

These 300 locomotives mostly formed class 5700 and became the standard pannier tank on the Great Western railway however they were not as standard as you think! 50 locomotives were built without steam heat, Vacuum braking and GWR ATC – This formed class 6700 and were used primarily for shunting and short trip freight work and as such weren’t equipped with screw couplings either, a simple 3 link chain was hung from the coupling hooks.

The 9700’s

Tagged on to the last batch of 5700 was a small build of ‘nearly’ pannier tanks that were built for working over London Transport metals to the Smithfield Market from Paddington. A radical departure from the appearance of the 5700, these had a shortened tank to make space for condensing equipment and weir pumps for feeding the boiler instead of injectors. To counter the loss of water capacity when the tanks were shortened, they were extended down to footplate level near the cab – which was also a new design with larger windows and more enclosed side sheets.

Later Orders

The larger and more comfortable cab on the 9700 class was incorporated into the latest breed of pannier tank. From 1933 the 8750 class was born. Nearly 500 locomotives followed to this basic design, right up until the last batch was completed by the Western region of British Railways in 1950. Like the 6700s before there was a further batch of no-heat and steam brake only locomotives, this time just ten were built and designated 6750 class. These, like the 6700s were outwardly identical to the parent class of which they belong.


The panniers benefitted from a low axle loading and were classified as ‘blue’ locomotives under the GWR’s route restriction policy. This allowed them to be utilised on pretty much the whole of the great western and later British Railways western region network. In fact, this blue coding was reduced to yellow in 1950 allowing them to reach even further branches around the country. The Great western also had its own power classification system which designated the panniers a ‘C’ which was later changed to 3F under the BR system.

The combination of power and route availability was enough to ensure that the near 800 members of this type were fully employed. They could be found on almost every type of traffic thinkable, from local pick-up freight trains to shunting yards, branch line passenger services to ECS and pilot duties at the bigger stations. They really were the go-anywhere, do-anything locomotives of the western region.

Withdrawals and post squadron service

The first withdrawals started in 1956 and continued through until 1966 when the class were removed from squadron service. Many locomotives were cut and disposed of, but some found employment elsewhere. Thirteen locomotives were purchased by London Transport to work night-time infrastructure trains over the Metropolitan line. These locomotives were modified with reduced width cab roofs and the removal of steam heating. Trip cocks were fitted which allowed them to integrate with London Transport’s signalling system – these were small valves that were actuated by a ramp when a signal was passed at danger. These locomotives were used until the grand finale of LT steam in 1971, 3 years after steam on the main British Railways network was abolished. London transport was not the only purchaser, the National Coal Board took advantage of the good quality locomotives that were being withdrawn. The NCB locomotives were worked hard and soldiered on until the last was withdrawn 1975.


The story does not stop there. Whilst some panniers were saved for preservation direct from BR the industrial and LT service gave preservationists a ‘second bite of the cherry’ and as a result many more locomotives were saved from the torch than would have been the case otherwise, in fact all surviving 5700s were preserved via this route. In total 16 locomotives, eight from the 5700 class and eight from the 8750 class are still with us.

These 16 have enjoyed a relatively relaxing retirement pottering around on the countries many preserved branch lines but variously 4 have been re-certified for mainline use and have been seen on many excursion trains running at speeds of up to 45mph

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