Indian locomotive class SG. The Indian locomotive class SG is a class of Indian steam locomotives used for goods trains. Its class designation, SG, stands for Standard Goods. It was, by number of locomotives built, one of the largest steam locomotive classes built in the United Kingdom. It was one of the BESA locomotives developed by the British Engineering Standards Committee, later called the British Engineering Standards Association (BESA).

History
With the growing demand for locomotives in the British Raj, it became increasingly difficult for British locomotive manufacturers to fulfill that need. To alleviate that problem, the British Engineering Standards Association (BESA) was commissioned to develop standard locomotive types. The first BESA report issued in 1903 recommended designs for a 4-4-0 standard passenger locomotive classified as SP and one for an 0-6-0 standard goods locomotive classified as SG. Later, revised editions of the BESA reports proposed eight classes of broad gauge locomotives and four classes of meter gauge locomotives for various services; these locomotives were later called BESA locomotives.

The SG class was used by the North Western State Railway (NWR), the Eastern Bengal Railway (EBR), the East Indian Railway (EIR) and the Oudh and Rohilkhand Railway (ORR) in India, hauling both goods and passenger trains. They could haul 1450 tons of freight with a speed of . Some locomotives were in service in India until the early 1980s and in Pakistan until the 1990s.

Design variants
A later variant designed with a Schmidt superheater was classified SGS (Standard Goods, Superheated). These locomotives received larger cylinders with piston valves and larger boilers, as well as a four-axle tender with bogies, as compared to their earlier designs which used saturated steam.

SG class locomotives retrofitted with superheaters were classified as SGC (Standard Goods, Converted). The SGSC class, later called SGC2, had round fireboxes instead of the Belpaire firebox of the original design. SGC3 class locomotives were retrofitted with superheaters and were fitted with the Lentz rotary valve gear. Despite their classifications, they frequently hauled passenger and mail trains.

A design variant classified as SG1 existed with unknown design characteristics.

Preservation

As of 2024, two example are known to survive into preservation, those being SGS 2473 and SGC-2 240. 

SGS 2473 was originally used by India Railways, before it was taken to Pakistan Railways. Withdrawn sometime in 1996, it saw mainline tour use until finally being taken out of use in 2010. It was then stored at Pakistan Railways’ workshops in Lahore. It is now at the Asfand Yar Bukhari Shaheed park on display. 

SGC-2 240 was originally used on the Eastern Bengal Railway from 1921 until 1936, by which it had been converted to burn oil. The locomotive would later be used as a shunter at Saidpur until 1983. It is now a plinth at Saidpur Railway Workshops.

See also
Indian Railways

Locomotives of India
Rail transport in India

References

Steam locomotives of India
5 ft 6 in gauge locomotives
0-6-0 locomotives
Vulcan Foundry locomotives
Robert Stephenson and Hawthorns locomotives
Freight locomotives
NBL locomotives
Steam locomotives of Bangladesh