LB&SCR K class

London Brighton and South Coast Railway K class
K class No. 337 as built
Type and origin Power type Steam Designer L. B. Billinton Builder Brighton Works Build date 1913–1921 Total produced 17 (completed) 3 (abandoned, partially built)
Specifications Configuration: ​  • Whyte 2-6-0  • UIC 1'C Gauge 4 ft 8 1⁄2 in (1,435 mm) standard gauge Leading dia. 3 ft 6 in (1.067 m) Driver dia. 5 ft 6 in (1.676 m) Wheelbase 23 ft 9 in (7.24 m) Length 57 ft 10 in (17.63 m) Total weight 105 long tons 5 cwt or 106.9 t or 117.9 short tons full Fuel capacity 4 LT or 4.1 t or 640.0 st Water cap 3,940 imp gal (17,911.59 l; 4,731.74 US gal) Firebox:  • Firegrate area 24.8 sq ft (2.30 m2) Boiler pressure 170 psi (1.17 MPa) Heating surface 1,573 sq ft (146.14 m2)  • Tubes 1,155 sq ft (107.30 m2) Superheater Robinson Cylinders Two, outside Cylinder size 21 in × 26 in (533 mm × 660 mm) Valve type Piston Valve travel 4 in (101.60 mm)
Performance figures Tractive effort 26,580 lbf (118.2 kN)
Career Operators London Brighton and South Coast Railway, Southern Railway, Southern Region of British Railways Class K Power class BR: 4P/5F Locale Great Britain First run February 1913 Withdrawn November–December 1962 Disposition All scrapped

London Brighton and South Coast Railway Class K were powerful 2-6-0 mixed traffic locomotives designed by L. B. Billinton for the London Brighton and South Coast Railway (LB&SCR) in 1913. They appeared shortly before the First World War and the first ten examples of the class did prodigious work during that conflict on munitions, supply and troop trains. Further examples were built after the war, and the class was used as a test bed for various items of specialised equipment. However, after the formation of the Southern Railway in 1923 the remaining three locomotives on order were not completed and the seventeen members of the class led relatively quiet yet reliable lives over their traditional lines. The locomotives proved their usefulness once again during the Second World War, and continued to provide reliable service until the 1960s. The entire class was eventually withdrawn in 1962 for 'bookkeeping' rather than 'operational' reasons.

Due to the nature of its traffic, the LB&SCR had relatively limited need of heavy freight locomotives. However, those it did have had to be able to accelerate quickly from sidings and signals and maintain a good speed if they were not going to impede the intensive use of the lines for passenger traffic, particularly in the London suburbs. This issue became increasingly problematic after about 1910 as more and more suburban lines were electrified. The rebuilding of Robert Billinton's C2 class with larger boilers, by D.E. Marsh solved this problem for a few years, but traffic continued to grow and by 1913 these were occasionally being double-headed. A larger and more powerful design was required for the heaviest freight trains, whilst there was also a continuing need for larger passenger locomotives, especially during the summer months. Lawson Billinton therefore ordered from Brighton works five powerful mixed-traffic locomotives which could cope with both types of load.