Notable features were a low boiler and large driving wheels. The crux of the Crampton patent was that the single driving axle was placed behind the firebox, so that the driving wheels could be very large. This helped to give this design a low centre of gravity, so that it did not require a very broad-gauge track to travel safely at high speeds. Its wheel arrangement was usually 4-2-0 or 6-2-0.
Design variations
Because the single driving axle was behind the firebox, Crampton locomotives usually had outside cylinders. However, some inside cylinder versions were built using indirect drive, then known as a jackshaft. The inside cylinders drove a crankshaft located in front of the firebox and the crankshaft was connected to the driving wheels by outside rods. Some long-wheelbase 0-4-0Ts were also built using this crankshaft system. The boiler feed-pump was often driven from the crankshaft as well because many Cramptons were built before the injector was invented.
Another feature on some Crampton locomotives was the use of a boiler of oval cross-section, to lower the centre of gravity. It was later seen as a major flaw, because the internal pressure would tend to push the boiler into a circular cross-section and increase the risk of fatigue.
Usage
Crampton locomotives were used by some British railways and speeds of up to 120 km/h (75 mph) were achieved on the LNWR. They were more popular in France, southern Germany and the US. In France the expression "prendre la Crampton" meant to catch an express, and in the argot of the Saint Cyr military academy, footplate staff were known as "officiers de Crampton" (and this as late as 1971). One of the French examples has been preserved in the Cité du Train (the French Railway Museum) at Mulhouse and is still in working order. This is number 80 of the Chemin de Fer de l'Est, the Paris-Strasbourg line, which is named "Le Continent".
Locomotive list
The approximate numbers of Crampton-type locomotives built in Europe were:
^ abcNamur was tested over 2,300 miles (3,700 km) on the LNWR[1] speeds up to 62 miles per hour (100 km/h) were recorded. Delivery of Namur, Liege and the third engine ordered for Belgium was delayed, and they were purchased by the South Eastern Railway in December 1849, becoming SER Nos 81, 83 and 85.
^Larger boiler and cylinders than Namur. Rebuilt as a goods 0-4-2 in 1855.[2][1]
Robert Stephenson and Company built a number of Crampton type locomotives for the South Eastern Railway and the London, Chatham and Dover Railway. These were all of 4-2-0 wheel arrangement with inside cylinders and indirect drive. The inside cylinders drove a crankshaft located in front of the firebox and the crankshaft was coupled to the driving wheels by outside rods.
^The name should have read Folkestone but was misspelled on the plate. This locomotive was displayed at The Great Exhibition of 1851.[3] Bogie wheels 3 feet 6 inches (1.07 m) diameter, driving wheels 6 feet (1.83 m) diameter. Cylinders 15 by 22 inches (381 mm × 559 mm). Weight 26 long tons 5 cwt (58,800 lb or 26.7 t).[4]
^LCDR Echo class; rebuilt as conventional 4-4-0s in 1865–1866.[6] They were not given numbers until 1874.
^Liverpool, 6-2-0, built by Bury, Curtis, and Kennedy works number 355 of 1848. Driving wheels 8 feet (2.44 m) diameter, grate area 21.5 square feet (2.00 m2), heating area 2,290 square feet (213 m2), boiler pressure 120 lbf/in2 (8.4 kgf/cm2; 830 kPa), cylinders 18 by 24 inches (457 mm × 610 mm). The locomotive was awarded a Gold Medal at the Great Exhibition of 1851.[1][7][2]
^Sources differ on how many Crampton locomotives Longridge built for the Great Northern Railway. Number 200 was later converted from a 4-2-0 to a conventional 2-2-2. There were nine similar 2-2-2 locomotives numbered 91-99 and it is uncertain whether these were built as 2-2-2 or whether they were converted from 4-2-0 like number 200.
^Phoenix of this series in service until 1903, length 12.90 metres (42 ft 4 in), top speed 120 kilometres per hour (75 mph), weight 28½ tonnes. Preserved in the Deutsches Bundesbahn Museum, Nuremberg.[20]
Baxter, Bertram (1978). Baxter, David (ed.). British Locomotive Catalogue 1825–1923, Volume 2A: London and North Western Railway and its constituent companies. Ashbourne, Derbyshire: Moorland Publishing Company. ISBN0-903485-51-6.