GER Class L77
|GER Class L77
LNER Class N7
N7/1 on a suburban train for Brentwood, c.1927
|Type and origin|
|Designer||A. J. Hill|
|UIC classification||C1 h2t|
|Gauge||4 ft 8 1⁄2 in (1,435 mm)|
|Driver diameter||4 ft 10 in (1.473 m)|
|3 ft 9 in (1.143 m)|
|Wheelbase||23 ft 0 in (7.01 m)|
|Length||34 ft 10 in (10.62 m) over buffers|
|Weight on drivers||49 long tons 4 cwt (110,200 lb or 50 t)|
|Locomotive weight||61.8–64.85 long tons (62.79–65.89 t)|
|Fuel capacity||3 long tons 5 cwt (7,300 lb or 3.3 t)|
|Water capacity||1,600 imperial gallons (7,270 l; 1,920 US gal)|
|Boiler pressure||180 psi (1.24 MPa)|
|Firegrate area||17.7 sq ft (1.64 m2)|
|1,291.7 sq ft (120.00 m2)|
|Cylinder size||18 in × 24 in (460 mm × 610 mm)|
|Tractive effort||20,512 lbf (91.24 kN)|
|Power class||BR: 3MT|
|Number in class||
|Axle load class||LNER/BR: Route availability 5|
|Disposition||One preserved, remainder scrapped|
The GER Class L77, LNER Class N7, is a class of 0-6-2T steam locomotives. They were designed by Alfred John Hill 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; only one of them is preserved.
The N7s had superheaters and piston valves. They were unusual (for inside-cylinder locomotives) in having Walschaerts valve gear. They were, as London suburban locomotives, fitted with Westinghouse air brakes.
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).
|Year||Order||Manufacturer||Quantity||GER Nos.||LNER Nos.||1946 Nos.||Notes|
|1915||L77||Stratford Works||2||1000–1001||8000–8001||9600–9601||Renumbered 7978–7979 in 1944|
|1921||K85||Stratford Works||10||1002–1011||8002–8011||9602–9611||Renumbered 7980–7989 in 1944|
|1925–26||—||Gorton Works||30||—||409, 421, 426, 456, 457, 460, 464, 471, 473, 475, 826–830, 832–834, 837, 838, 850–853, 865–868, 870, 873||9622–9651||Class N7/1|
|1925–26||—||Robert Stephenson & Co.||20||—||907, 912, 913, 916, 918, 919, 935, 940, 941, 947, 950, 952, 964, 966–968, 970, 971, 987, 988||9652–9671||Class N7/1|
|1927–28||—||Gorton Works||10||—||2632–2641||9672–9681||Class N7/2|
|1927||—||Wm. Beardmore & Co.||20||—||2642–2661||9682–9701||Class N7/2|
|1927–28||—||Doncaster Works||32||—||2600–2631||9702–9733||Class N7/3|
- N7 Introduced 1914, GER Class L77 with Belpaire firebox
- 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(1)Introduced 1927, LNER locos with round-top firebox
- N7/3(2)Introduced 1943, rebuild of N7/1 with round-top firebox
- N7/3(3)Introduced 1943, rebuild of N7/2 with round-top firebox
- N7/4 Introduced 1940, GER locos rebuilt with round-top firebox
One, No. 7999 (BR No. 69621) has been preserved and is currently operational. It is owned by the East Anglian Railway Museum. 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.
- Aldrich, C. Langley (1969). The Locomotives of the Great Eastern Railway 1862–1962 (7th ed.). Wickford, Essex: C. Langley Aldrich. OCLC 30278831.
- Boddy, M. G.; Brown, W. A.; Fry, E. V.; Hennigan, W.; Hoole, Ken; Manners, F.; Neve, E.; Platt, E. N. T.; Proud, P.; Yeadon, W. B. (March 1977). Fry, E. V., ed. Locomotives of the L.N.E.R., Part 9A: Tank Engines—Classes L1 to N19. Kenilworth: RCTS. ISBN 0-901115-40-1.
- Ian Allan ABC of British Railways Locomotives, 1948 edition, part 4, pp 54–55
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