LSWR/SR G6[1][page needed]
Adams G6 No. 240 is stored pending scrapping following withdrawal from service at Eastleigh, 1949
Type and origin Power type Steam Designer William Adams Builder LSWR Nine Elms Works Build date 1894–1900 Total produced 34
Specifications Configuration: ​  • Whyte 0-6-0T Gauge 4 ft 8+1⁄2 in (1,435 mm) Driver dia. 4 ft 10 in (1.473 m) Length 30 ft 8+1⁄2 in (9.36 m) Loco weight 37.65 long tons (38.3 t) Fuel type Coal Fuel capacity 1.5 long tons (1.5 t); later 3.25 long tons (3.3 t) Water cap. 1,000 imp gal (4,500 L) Boiler pressure 160 lbf/in2 (1.10 MPa) Cylinders Two, inside Cylinder size 17+1⁄2 in × 24 in (444 mm × 610 mm)
Performance figures Tractive effort 17,235 lbf (76.67 kN)
Career Operators London and South Western Railway Southern Railway British Railways Class LSWR: G6 SR: G6 Power class SR: (none) BR: 2F Locale Southern Region Withdrawn 1948–1962 Disposition All scrapped

The LSWR G6 class was an 0-6-0T tank locomotive designed by William Adams for the London and South Western Railway.

The late nineteenth century was a troubled period for the LSWR due to frequent motive power shortages brought about by employing a collection of ageing locomotives in an era of increasing rail traffic. There was a need to supplement this fleet with a new class of locomotive design that could undertake the mundane task of shunting in goods yards around the LSWR network.

In 1893, the LSWR tasked their Locomotive Superintendent, William Adams, to solve this requirement for additional motive power.^{[2][page needed]} A new class of yard shunters was required to supplement the railway's current stock of 0-6-0Ts, which dated from 1881 and had been constructed by Beyer, Peacock and Company.^{[2][page needed]} Therefore, a need for a compact freight design was highlighted, with the G6 being the resultant locomotive class.^{[2][page needed]}

The new design was designated the Class G6 by Adams, who intended the class to be an 0-6-0 version of his O2 class passenger locomotives.^{[3][page needed]} The wheel arrangement was ideal for the tight curves and traction needed in shunting activities, with the shorter wheelbase helping to solve both these concerns. The G6 represented the only 0-6-0 design undertaken by Adams, with the resultant locomotive being a highly compact design.^{[3][page needed]} Construction of the class began in 1893, and was undertaken in-house by the LSWR at Nine Elms works in London, with an initial batch of ten locomotives being constructed. The boiler also betrayed the pairing with the O2 Class because it was the same for standardisation purposes.

Four further locomotives were constructed in 1896 as replacements for the B4 class 0-4-0T dock shunters at Southampton Docks due to their increased coal and water capacity and enhanced power.^{[2][page needed]} This proved to be one of Adams's last deeds on the LSWR, as he retired to be replaced by Dugald Drummond.

Drummond authorised a further batch of ten locomotives during the period 1897 to 1898 after being impressed with the performance of the class. A further, and final, batch of ten was ordered in 1900.^{[2][page needed]} However, both of these batches differed from the original ten because they utilised the boilers of Beattie Well tanks and other withdrawn locomotives.^{[2][page needed]} Very few modifications were undertaken during their working careers, with only the Adams stovepipe chimney being replaced by a Drummond lipped example, whilst vacuum brakes were also eventually implemented.^{[2][page needed]}

Under LSWR ownership, the G6s were outshopped in the LSWR dark Holly Green livery, with black and light green lining, which was applied to most freight designs of the LSWR. Gilt lettering and numbering was located on the water tank sides and cabside respectively, with the letters 'LSW.'^{[4][page needed]}

The class as inherited by British Railways retained the Southern livery for a short period. As overhauls took place, the class began to be turned out in unlined BR Freight Black livery.^{[3][page needed]} However, only ten locomotives were to see this livery, as several members were withdrawn from service and scrapped. The BR crest was placed upon the water tank sides, with the number cabside.^{[3][page needed]}

Due to the confused nature of the original LSWR and subsequent SR numbering systems, the class was spread across several numbering bands in the BR 30xxx series. BR inherited 32 locomotives: 30160, 30162, 30257 to 30279, and 30348, 30349.^{[3][page needed]} However, after the mass withdrawal of 1951, only 30160, 30162, 30237, 30258, 30260, 30266, 30270, 30274, 30279 and 30349 remained to receive the new livery.

The G6 Class was a highly localised, though useful, locomotive design that very rarely ventured off the LSWR network, even in service with the Southern Railway. The only exception was the transfer of a single example to Reading freight yard in 1941 to assist with the GWR's shortage of motive power during the Second World War.^{[3][page needed]} As the war progressed, a second member of the class was also transferred here and provided sterling service.

The class was highly successful in undertaking the tasks they were designed for, and were respected by their crews. They rarely undertook passenger work, though they did undertake banking duties between Exeter St Davids and Exeter Central on occasion, until Stroudley E1/R 0-6-2Ts took on this task in 1933.^{[3][page needed]}

After Nationalisation, two members of the class eventually found their way into departmental service, both being allocated to Meldon Quarry in Devon. The first to undertake this role was number 30272 in June 1950, being renumbered DS3152. When this example was withdrawn in 1960, 30238 replaced DS3152 under the new number of DS682.^{[5][page needed]}

The first withdrawal was number 348 in August 1948, followed by a larger number of 22 by the end of 1951.^{[5][page needed]} The final survivor was a 64-year-old example, number 30238, though this locomotive was one of the last to be withdrawn as part of the Modernisation Plan in late 1962.^{[5][page needed]} None of these useful locomotives have survived into preservation.