The GER Class L77,

LNER LNER may refer to: * London and North Eastern Railway, a railway company in the United Kingdom from 1923 until 1947 * London North Eastern Railway, a train operating company in the United Kingdom since 2018 * Liquid neutral earthing resistor, a typ ...

Class N7, is a class of

0-6-2T T, or t, is the twentieth letter in the modern English alphabet and the ISO basic Latin alphabet. Its name in English is ''tee'' (pronounced ), plural ''tees''. It is derived from the Semitic letters taw (ת, ܬ, ت) via the Greek letter ...

steam locomotives 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 ...

. They were designed by

Alfred John Hill Alfred John Hill (1 January 1862–1 January 1927) was Chief Mechanical Engineer at the Stratford Works of the Great Eastern Railway from 1912 to 1922. His best-known design is probably the GER Class L77 0-6-2 tank locomotive which was perpet ...

of the Great Eastern Railway and introduced in 1915. The design was perpetuated by Nigel Gresley of the LNER after the 1923 grouping. 134 were built and one example is preserved.

Overview

The N7s had superheaters and

piston valve A "piston valve" is a device used to control the motion of a fluid along a tube or pipe by means of the linear motion of a piston within a chamber or cylinder. Examples of piston valves are: * The valves used in many brass instruments * The va ...

s. They were unusual (for inside-cylinder locomotives) in having

Walschaerts valve gear The Walschaerts valve gear is a type of valve gear used to regulate the flow of steam to the pistons in steam locomotives, invented by Belgian railway engineer Egide Walschaerts in 1844. The gear is sometimes named without the final "s", since it ...

. They were, as London suburban locomotives, fitted with Westinghouse air brakes. Some were fitted with condensing apparatus for working on the Metropolitan line and the East London Line but the condensing apparatus was removed between 1935 and 1938.

Numbering

The first 22 were allocated numbers in the 990–1011 range when ordered by the GER, but the last 10 did not emerge until the grouping. The LNER added 7000 to their GER numbers, and then built a further 112 locomotives between 1925 and 1928. In the 1946 renumbering scheme, they were renumbered 9600–9733, and upon nationalisation in 1948, British Railways added 60000 to their number (69600–69733).

Sub-classes

St Margarets station with Liverpool Street train geograph-2886847-by-Ben-Brooksbank

* N7 Introduced 1914, GER Class L77 with

Belpaire firebox The Belpaire firebox is a type of firebox used on steam locomotives. It was invented by Alfred Belpaire of Belgium in 1864. Today it generally refers to the shape of the outer shell of the firebox which is approximately flat at the top and sq ...

* N7/1 Introduced 1925, LNER development of GER design with Belpaire firebox * N7/2 Introduced 1926, LNER locos with Belpaire firebox and long-travel valves * N7/3 Introduced 1927, LNER locos with round-top firebox, plus from 1943, rebuilds of N7/2 with round-top firebox * N7/4 Introduced 1940, GER locos rebuilt with round-top firebox * N7/5 Introduced 1943, N7/1 locos rebuilt with round-top firebox

Accidents and incidents

*On 24 May 1954, locomotive No. 69638 ran into the turntable pit at

Hatfield, Hertfordshire Hatfield is a town and civil parish in Hertfordshire, England, in the borough of Welwyn Hatfield. It had a population of 29,616 in 2001, and 39,201 at the 2011 Census. The settlement is of Saxon origin. Hatfield House, home of the Marquess o ...

following the removal of the turntable.

Preservation

One LNER example, No. 7999 (BR No. 69621) has been preserved and is currently on static display pending overhaul at the East Anglian Railway Museum at Chappel & Wakes Colne. It is owned by the

East Anglian Railway Museum The East Anglian Railway Museum is located at Chappel and Wakes Colne railway station in Essex, England, which is situated on the former Great Eastern Railway branch line from Marks Tey to Sudbury. Services on the Sudbury Branch Line are ...

. It was the last engine built by the Great Eastern Railway's Stratford Works in 1924 and was preserved in 1962. It was also named in honour of its designer A J Hill in 1989.

References

Sources

* * * * Ian Allan ABC of British Railways Locomotives, 1948 edition, part 4, pp 54–55