The Great Northern Railway (GNR) Class L1 (LNER Class R1) was a 0-8-2T

side tank A tank locomotive or tank engine is a steam locomotive that carries its water in one or more on-board water tanks, instead of a more traditional tender. Most tank engines also have bunkers (or fuel tanks) to hold fuel; in a tender-tank locomot ...

steam locomotive A steam locomotive is a locomotive that provides the force to move itself and other vehicles by means of the expansion of steam. It is fuelled by burning combustible material (usually coal, oil or, rarely, wood) to heat water in the locomot ...

Henry Ivatt Henry Alfred Ivatt (16 September 1851, Wentworth, Cambridgeshire – 25 October 1923) was an English railway engineer, and was the Chief Mechanical Engineer of the Great Northern Railway from 1896 to 1911. Career London and North Western ...

. It was originally designed for suburban passenger traffic on the Metropolitan City Lines. A prototype was built in 1903, but it was overweight, so it was rebuilt with a smaller boiler and shorter side tanks. Ten more engines were then built to this modified design. During the "small boiler" era, the cylinders were lined to 18" to match the boilers. In 1905 and 1906, thirty more engines were built for working goods trains in the

West Riding of Yorkshire The West Riding of Yorkshire is one of three historic subdivisions of Yorkshire, England. From 1889 to 1974 the administrative county County of York, West Riding (the area under the control of West Riding County Council), abbreviated County ...

. The original eleven engines were not a great success on passenger services so, in 1907, they were moved to the West Riding for goods work.

Condensing apparatus

The first eleven locomotives were fitted with condensing apparatus for working in tunnels. The thirty built for the West Riding were probably not so fitted, but this is subject to confirmation. It is not known whether the condensing apparatus was removed from the original eleven when they were moved to the West Riding.

Modifications

Between 1909 and 1926 the locomotives were gradually rebuilt with larger boilers to the original specification. Seven locomotives had

superheater A superheater is a device used to convert saturated steam or wet steam into superheated steam or dry steam. Superheated steam is used in steam turbines for electricity generation, steam engines, and in processes such as steam reforming. There ar ...

s fitted and, on these, the working pressure was reduced to 170 psi.

Proposed diesel conversion

In 1932 there was a proposal to convert some of the locomotives to diesel power. The

prime mover Prime mover may refer to: Philosophy *Unmoved mover, a concept in Aristotle's writings Engineering * Prime mover (engine), motor, a machine that converts various other forms of energy (chemical, electrical, fluid pressure/flow, etc) into energy o ...

would have been an 8-cylinder

diesel engine The diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the diesel engine is a so-call ...

of 400 horsepower, driving a 4-cylinder

air compressor An air compressor is a pneumatic device that converts power (using an electric motor, diesel or gasoline engine, etc.) into potential energy stored in pressurized air (i.e., compressed air). By one of several methods, an air compressor forces ...

to charge an air reservoir. Compressed air from the reservoir would have been heated, both by the diesel exhaust and by steam from an oil-fired

steam generator A Steam generator is a device used to boil water to create steam. More specifically, it may refer to: *Boiler (steam generator), a closed vessel in which water is heated under pressure *Monotube steam generator *Supercritical steam generator or Ben ...

, and would then have entered the locomotive's original cylinders at about 150 psi. The use of steam to heat the air is reminiscent of the

Mekarski system The Mekarski system was a compressed-air propulsion system for trams invented by Louis Mékarski or Louis Mékarsky (the correct spelling is uncertain) in the 1870s. He worked in France, was born in 1843 in Clermont-Ferrand (center of France) ...

. This diesel-pneumatic proposal never became a reality but a German one of 1929 did.

Withdrawal

The engines were withdrawn between 1927 and 1934 and none are preserved.

References

L1 0-8-2T locomotives Railway locomotives introduced in 1903 Scrapped locomotives Standard gauge steam locomotives of Great Britain D1′ n2t locomotives {{England-steam-loco-stub Passenger locomotives