LNER Class B12

GER Class S69
LNER Class B12

B12/4 4-6-0 No. 61504 at Keith Locomotive Depot 1948

Type and origin Power type Steam Designer S. D. Holden Builder Stratford Works (51), Wm. Beardmore & Co. (20), Beyer, Peacock & Co. (10) Serial number WB 135–154, BP 6487–6496 Build date 1911–1928 Total produced 81

Specifications Configuration 4-6-0 UIC class 2′C h2t Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Leading dia. 3 ft 3 in (0.991 m) Driver dia. 6 ft 6 in (1.981 m) Wheelbase 48 ft 3 in (14.71 m) Length 57 ft 7 in (17.55 m) over buffers Adhesive weight B12/1&2: 43 long tons 8 cwt (97,200 lb or 44.1 t) B12/3: 48 long tons 2 cwt (107,700 lb or 48.9 t) Loco weight B12/1&2: 62 long tons 19.5 cwt (141,100 lb or 64 t) B12/3: 69 long tons 5 cwt (155,100 lb or 70.4 t) Tender weight 38 long tons 6 cwt (85,800 lb or 38.9 t) Fuel type Coal Fuel capacity 4 long tons 0 cwt (9,000 lb or 4.1 t) Water cap 3,700 imp gal (16,800 l; 4,440 US gal) Firebox:  • Firegrate area 26.5 sq ft (2.46 m2) Boiler pressure 180 psi (1.24 MPa) Heating surface 1,919 sq ft (178.3 m2)  • Firebox 154 sq ft (14.3 m2) Cylinders Two, inside Cylinder size 20 in × 28 in (510 mm × 710 mm)

Performance figures Tractive effort 21,969 lbf (97.72 kN)

Career Operators Great Eastern Railway → London and North Eastern Railway → British Railways Class GER: S69, LNER: B12 Power class BR: 4P3F Axle load class LNER/BR: RA 4 (B12/3), RA 3 (remainder) Withdrawn 1913 (1), 1945–1961 Disposition One preserved, remainder scrapped

The Great Eastern Railway (GER) Class S69, also known as 1500 Class, and later classified B12 by the London and North Eastern Railway (LNER) is a class of 4-6-0 steam locomotive designed to haul express passenger trains from London Liverpool Street station along the Great Eastern Main Line. Originally they were designed by S. D. Holden, but were much rebuilt, resulting in several subclasses.

Seventy-one S69 locomotives were built by the GER between 1911 and 1921 and numbered 1500–1570. A further 10 locomotives were built by Beyer, Peacock & Co for the LNER in 1928 and numbered 8571–8580. From 1948 the British Railways numbers were 61500–61580 (with gaps).

At the time of their introduction, the "Claud Hamilton" 4-4-0s were becoming outclassed on the heaviest express. Although an enlarged 4-4-0 design was mooted, it was realised that any such design would have too high an axle load for the tracks of the Great Eastern Railway, which had a relatively low restriction. Another design constraint was the short turntables used at the time. This meant that a 4-6-0 design was decided upon, although the design was relatively short compared to similar designs introduced at the same time.

Seventy were still in service at the 1923 grouping, the LNER adding 7000 to the numbers of nearly all the ex-Great Eastern locomotives, including the Class S69 locomotives. A further ten were ordered in 1928 to ease a power shortage caused by the stalled development on a new class of 4-6-0 locomotives, and the cancellation of the planned suburban 2-6-4T tank locomotive due to the adverse press publicity caused by the Sevenoaks derailment.