The War Department (WD) "Austerity" 2-10-0 is a type of heavy freight steam locomotive that was introduced during the Second World War in 1943.

The Austerity 2-10-0 was based on the Austerity 2-8-0, and was designed to have interchangeable parts by R.A. Riddles. It had the same power output as the 2-8-0 but a lighter axle load, making it suitable for secondary lines.^[1]

It had a parallel boiler and round-topped firebox. While the 2-8-0 had a narrow firebox, the 2-10-0 had a wide firebox placed above the driving wheels. This arrangement was common in the United States (e.g. the USRA 0-8-0) but unusual in Britain, where wide fireboxes were usually used only where there was a trailing bogie, e.g. in 4-4-2 and 4-6-2 types. These were the first 2-10-0 locomotives to work in Great Britain, and the first major class of ten-coupled engines — they had been preceded by two 0-10-0 locomotives; the Great Eastern Railway's Decapod and the Midland Railway's Lickey Banker. The 2-10-0 wheel arrangement was later used by Riddles when he designed the BR Standard Class 9F. This, too, had a wide firebox placed above the driving wheels.

Two batches were built by the North British Locomotive Company, the first batch of 100 introduced in 1943/1944 and the second batch of 50 in 1945. Their WD Nos were 3650–3749 (later 73650–73749), and 73750–73799.

20 of the first batch were sent to the Middle East. During running-in they worked in Britain, but their length made them unsuitable. Most saw service with the British Army in France after D-Day in the drive towards the Siegfried Line.^[2]

After the war the 150 locomotives were distributed as follows, the majority going to the Netherlands:

In the 1952 WD renumbering scheme, the two remaining in WD service (at the Longmoor Military Railway), Nos. 73651 and 73797, were renumbered 600 and 601 respectively. The also received names: 600 Gordon and 601 Kitchener.

LMR 600 Gordon has survived and has been steamed on the Severn Valley Railway, though as of 2022^[update] it is out of service, cosmetically restored and on display in the Engine House.

Two more have been repatriated from Greece. One has been numbered 90775, one higher than the last BR engine, and has carried the name Sturdee^{[note 1]} (as WD/LMR No. 601 before being numbered 90775) and is operational on North Norfolk Railway where it has now been renamed The Royal Norfolk Regiment as of 2022.^[3] The other is WD No. (7)3672 which has been named Dame Vera Lynn. The loco is currently being overhaul at Grosmont on the NYMR.

The 4th one in preservation WD 73755 (NS 5085) survives in the Dutch Railway Museum (Nederlands Spoorwegmuseum) in Utrecht. It carries the nameplate Longmoor, after the Royal Engineers base at Longmoor, with the coat of arms of the Royal Engineers above.

Four locomotives remain in various states in Greece with Λβ962 and Λβ964 operating mainline tours on the Drama to Xanthi line. Other locomotives remain in poor states stored awaiting further use.

Of the eight surviving members of the class, three have run on the main line: nos. 600 Gordon, 73677 & 73682. Gordon appeared at the Rail 150 celebrations in August 1975 and traveled to Shildon and later returned to the SVR under its own steam, in 1980 it travelled under its own power to Bold Colliery to take part in the locomotive parade at Rocket 150 in Rainhill.^[10] Due to the class's flangeless centre driving wheels, there is a concern that the raised check rails on modern pointwork might cause a derailment, so the class (alongside other 2-10-0 locomotives) are presently prohibited from operating on the mainline in Great Britain.

73677 and 73682 have both worked on the national network in Greece, neither are presently operational.

* Name or number applied after preservation

• BR ex-WD Austerity 2-10-0 - locomotives taken into LNER/BR ownership
• WD Austerity 2-8-0 - locomotives of similar design