GER Decapod
Encyclopedia
The GER Class A55 or Decapod was an experimental steam locomotive
with an 0-10-0T wheel arrangement
designed by James Holden
for the Great Eastern Railway
. It was the first ten-coupled steam locomotive in Great Britain
.
The locomotive was built for purely political purposes in order to block the passage through Parliament of a new rival scheme for an electric railway.
The Decapod was built in 1902 to a design by the GER Chief Draughtsman, Fred Russell under the supervision of the Chief Superintendent, James Holden
. The aim was to demonstrate the ability of a steam locomotive to accelerate passenger trains at a rate comparable to electric traction and the electric trams with which the GER was also in competition over short distances.
The locomotive was far larger than any locomotive previously built in Britain for home service. It had 10 four-foot-six-inch driving wheel
s, which gave high tractive effort
. Three cylinders were used because there was insufficient room for two cylinders large enough to develop the required tractive effort without going up to a higher boiler pressure. Even so, it still had to have a pressure of 200 psi
(1,378 kPa
) to achieve the required result.
(305 tonne) train from a stand to 30 mi/h in 30 seconds. According to Ahrons, "Holden's engine actually accelerated a new train of 18 carriages weighing 335 tons (340 tonnes) at a rate of 1.4 feet/second in very windy weather".
Axle load at 16.75 tons (17 tonnes), was not excessive, but weight per foot run of wheelbase was very high and using a class of these engines would have necessitated considerable strengthening of bridges; thus whilst it achieved its aims, nothing resulted from the experiment.
freight tender engine. The rebuild included a new boiler with a Belpaire firebox
and a standard GE high-sided goods locomotive tender.
Number 20 was then assigned to March district for hauling coal trains, but proved no more capable than the Class G58
locomotives. The design was therefore not repeated, and the locomotive remained the only eight-coupled engine of the GER.
It was scrapped in 1913 as nonstandard after a short working life.
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 2-10-0
s 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
.
Steam locomotive
A steam locomotive is a railway locomotive that produces its power through a steam engine. These locomotives are fueled by burning some combustible material, usually coal, wood or oil, to produce steam in a boiler, which drives the steam engine...
with an 0-10-0T wheel arrangement
Wheel arrangement
In rail transport, a wheel arrangement is a system of classifying the way in which wheels are distributed beneath a locomotive.. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and connections, with the adopted notations varying by country...
designed by James Holden
James Holden (engineer)
James Holden was an English locomotive engineer.He is remembered mainly for the "Claud Hamilton" 4-4-0, his pioneering work with oil fuel, and his unique "Decapod".- Biography :...
for the Great Eastern Railway
Great Eastern Railway
The Great Eastern Railway was a pre-grouping British railway company, whose main line linked London Liverpool Street to Norwich and which had other lines through East Anglia...
. It was the first ten-coupled steam locomotive in Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
.
Background
The Decapod was built in 1902 to a design by the GER Chief Draughtsman, Fred Russell under the supervision of the Chief Superintendent, James Holden
James Holden (engineer)
James Holden was an English locomotive engineer.He is remembered mainly for the "Claud Hamilton" 4-4-0, his pioneering work with oil fuel, and his unique "Decapod".- Biography :...
. The aim was to demonstrate the ability of a steam locomotive to accelerate passenger trains at a rate comparable to electric traction and the electric trams with which the GER was also in competition over short distances.
The locomotive was far larger than any locomotive previously built in Britain for home service. It had 10 four-foot-six-inch driving wheel
Driving wheel
On a steam locomotive, a driving wheel is a powered wheel which is driven by the locomotive's pistons...
s, which gave high tractive effort
Tractive effort
As used in mechanical engineering, the term tractive force is the pulling or pushing force exerted by a vehicle on another vehicle or object. The term tractive effort is synonymous with tractive force, and is often used in railway engineering to describe the pulling or pushing capability of a...
. Three cylinders were used because there was insufficient room for two cylinders large enough to develop the required tractive effort without going up to a higher boiler pressure. Even so, it still had to have a pressure of 200 psi
Pounds per square inch
The pound per square inch or, more accurately, pound-force per square inch is a unit of pressure or of stress based on avoirdupois units...
(1,378 kPa
Pascal (unit)
The pascal is the SI derived unit of pressure, internal pressure, stress, Young's modulus and tensile strength, named after the French mathematician, physicist, inventor, writer, and philosopher Blaise Pascal. It is a measure of force per unit area, defined as one newton per square metre...
) to achieve the required result.
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 42 sq ft (3.9 m²). The trailing drivers were given a side play of 0.5 in (12.7 mm), 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.Performance
The specification required that the locomotive should accelerate 315 tonLong ton
Long ton is the name for the unit called the "ton" in the avoirdupois or Imperial system of measurements, as used in the United Kingdom and several other Commonwealth countries. It has been mostly replaced by the tonne, and in the United States by the short ton...
(305 tonne) train from a stand to 30 mi/h in 30 seconds. According to Ahrons, "Holden's engine actually accelerated a new train of 18 carriages weighing 335 tons (340 tonnes) at a rate of 1.4 feet/second in very windy weather".
Axle load at 16.75 tons (17 tonnes), was not excessive, but weight per foot run of wheelbase was very high and using a class of these engines would have necessitated considerable strengthening of bridges; thus whilst it achieved its aims, nothing resulted from the experiment.
Rebuilt
As the locomotive was therefore surplus to requirements, it was rebuilt in 1906, and converted into an 0-8-00-8-0
Under the Whyte notation for the classification of steam locomotives, 0-8-0 represents the wheel arrangement of no leading wheels, eight powered and coupled driving wheels on four axles, and no trailing wheels...
freight tender engine. The rebuild included a new boiler with a Belpaire firebox
Belpaire firebox
The Belpaire firebox is a type of firebox used on steam locomotives. It was invented by Alfred Belpaire of Belgium. It has a greater surface area at the top of the firebox, improving heat transfer and steam production...
and a standard GE high-sided goods locomotive tender.
Number 20 was then assigned to March district for hauling coal trains, but proved no more capable than the Class G58
GER Class G58
The GER Class G58 was a class of 0-6-0 steam tender locomotives designed by James Holden for the Great Eastern Railway. The class consisted partly of new locomotives built 1905–1911 and partly of rebuilds of the earlier GER Class F48, originally built 1900–1903...
locomotives. The design was therefore not repeated, and the locomotive remained the only eight-coupled engine of the GER.
It was scrapped in 1913 as nonstandard after a short working life.
0-10-0 developments
The Midland RailwayMidland Railway
The Midland Railway was a railway company in the United Kingdom from 1844 to 1922, when it became part of the London, Midland and Scottish Railway....
produced the second 0-10-0 locomotive in 1919 with its MR 0-10-0 Lickey Banker
MR 0-10-0 Lickey Banker
In 1919, the Midland Railway built a single 0-10-0 steam locomotive, No 2290 . It was designed by James Clayton for banking duties on the Lickey Incline in Worcestershire , England...
. The third ten-coupled engine however would not appear until 1943 in the guise of a class of 2-10-0
2-10-0
Under the Whyte notation for the classification of steam locomotives, 2-10-0 represents the wheel arrangement of two leading wheels on one axle, ten powered and coupled driving wheels on five axles, and no trailing wheels...
s built by the War Department
War Department (UK)
The War Department was the United Kingdom government department responsible for the supply of equipment to the armed forces of the United Kingdom and the pursuance of military activity. In 1857 it became the War Office...
, the Austerity 2-10-0
WD Austerity 2-10-0
The War Department "Austerity" 2-10-0 is a type of heavy freight steam locomotive that was introduced during the Second World War in 1943.-Background:...
. These were followed in 1954 by the last class of British ten-coupled engines, the BR standard class 9F
BR standard class 9F
The British Railways BR Standard Class 9F 2-10-0 is a class of steam locomotive designed for British Railways by Robert Riddles. The Class 9F was the last in a series of standardised locomotive classes designed for British Railways during the 1950s, and was intended for use on fast, heavy freight...
.
External links
- http://mikes.railhistory.railfan.net/r075.html