GER Decapod
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| Power type | Steam |
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| Designer | James Holden |
| Build date | 1902 |
| Configuration | 0-10-0; rebuilt in 1906 as 0-8-0 |
| Driver size | 5 ft 4 in (1625.6 mm) |
| Total weight | 70 tons |
| Boiler | length: 15 ft 6 in inside dia: 5 ft 3 in |
| Heating surface: Tubes | 395 x 1¾ in dia |
| Heating surface: Firebox | 131.7 ft² |
| Heating surface: Total | 2,873.3 ft² |
| Cylinders | 3 |
| Cylinder size | 18½ in dia x 24 in stroke |
| Career | Great Eastern Railway |
| Disposition | scrapped |
The Great Eastern Railway's Decapod was an experimental steam locomotive with an 0-10-0 wheel arrangement. It was the first ten coupled steam locomotive in Great Britain.
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[edit] Background
The Decapod was built in 1902 to a design by James Holden to demonstrate the ability of a steam locomotive to accelerate passenger trains comparable to electric traction and the electric trams with the GER was in competition over short distances. It was heavy and had 10 small driving wheels. This developed power and thus acceleration, but limited its top speed. It could accelerate a 300ton train from a stand to 30mph in 30seconds. Three cylinders were used because there was insufficient room for 2 cylinders large enough to develop the required tractive effort without going up to a higher boiler pressue. Even so, it still had to have a pressure of 250lb to achieve the required result
Its weight produced its major flaw; its high axle loading. Despite the water being located in a well tank beneath the bunker, strengthening of bridges was found to be uneconomical and thus although it achieved its aims, nothing resulting from the experiment.
In 1906 it was converted into an 0-8-0 freight tender engine, the only eight coupled engine of the GER and was scapped as non-standard after a short working life.
[edit] Technical details
There were three separate grates and ash pans, one on each side outside the frames and a third between, giving an aggregate area of 42sq. ft. The trailing drivers were given a side play of ½", the coupling rods being fitted with ball and socket joints. As the cranks of the three cylinders were set at 120 degrees in relation to each other, perfect balancing of the reciprocating parts was secured. In order to minimise the drivers slipping, compressed air sanders were fitted.
[edit] 0-10-0 Developments
The Midland Railway produced the second 0-10-0 locomotive in 1919 with its MR 0-10-0 Lickey Banker. The third ten coupled engine however would not appear until 1943 in the guise of a class of 2-10-0s built by the War Department, the Austerity 2-10-0. These were followed in 1954 by the last class of British ten coupled engines, the BR standard class 9F.
