GER Class L77

GER Class L77
LNER Class N7

N7/1 on a suburban train for Brentwood, c.1927

Type and origin Power type Steam Designer A. J. Hill Builder Stratford Works (22) Gorton Works (40) Robert Stephenson & Co. (20) William Beardmore & Co. (20) Doncaster Works (32) Build date 1915–1928 Total produced 134

Specifications Configuration 0-6-2T UIC class C1 h2t Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Driver dia. 4 ft 10 in (1.473 m) Trailing dia. 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 Adhesive weight 49 long tons 4 cwt (110,200 lb or 50 t) Loco weight 61.8–64.85 long tons (62.79–65.89 t) Fuel type Coal Fuel capacity 3 long tons 5 cwt (7,300 lb or 3.3 t) Water cap 1,600 imperial gallons (7,270 l; 1,920 US gal) Firebox:  • Firegrate area 17.7 sq ft (1.64 m2) Boiler pressure 180 psi (1.24 MPa) Heating surface 1,291.7 sq ft (120.00 m2) Cylinders Two, inside Cylinder size 18 in × 24 in (457 mm × 610 mm) Valve gear Walschaerts

Performance figures Tractive effort 20,512 lbf (91.24 kN)

Career Operators Great Eastern Railway → London and North Eastern Railway → British Railways Class GER: L77 LNER: N7 Power class BR: 3MT Number in class 1 January 1923: 12 1 January 1948: 134 Axle load class LNER/BR: Route availability 5 Withdrawn 1957–1962 Disposition One preserved, remainder scrapped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.

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.

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).

One, 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. 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.