GER Class A55 Decapod
Design and development
The London suburban traffic was being threatened in the early 1900s by electrification (notably the Metropolitan and District Railways' programme), and Parliament was pressing the GER to electrify its London suburban network. James Holden, the GER's locomotive engineer, argued that steam could match the electrics' acceleration if a sufficiently powerful engine were built. To prove the point, he designed in 1902 a unique 0-10-0 tank engine — Decapod — with three cylinders, a vast firebox, and ten coupled wheels for adhesion.
Tested in 1903 with a representative GER suburban train, Decapod successfully achieved 30 mph in 30 seconds — matching the District Railway electrics. The demonstration succeeded in winning the GER a parliamentary reprieve from compulsory electrification.
Service and withdrawals
Decapod was however too heavy for the GER's track and bridges, and was never put into regular service. It was rebuilt as an 0-8-0 tender goods engine in 1908, then withdrawn and scrapped in 1913. None of the original Decapod survives.
Identification features
Unique 0-10-0 tank with three cylinders, ten coupled wheels with no carrying axles, large side tanks and rear bunker, very large firebox. The only British 0-10-0 ever built.
Notable locomotives
- 20 Decapod (1902, not preserved — scrapped 1913)