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The British Engineering Standards Committee (BESC, later renamed to the British Engineering Standards Association), founded in 1901, envisioned standardised locomotive classes for use in British India, to improve production and maintenance. In the second edition of the BESA report on British Indian standard locomotive classes of 1907, the HG class, designed for heavy goods trains, was first mentioned. As with the AP and HP class passenger locomotives, the HG was provided with three different tenders: the smaller 3000 gallon and 4000 gallon three-axle tenders, and the larger 4500 gallon bogie tender.
In addition, the 1907 BESA report also catalogued two variants: Variant A with 5 ft 1+1⁄2 in (1,562 mm) diameter driving wheels, which was proposed by the Indian Railways Ministry, and Variant B with 4 ft 8+1⁄2 in (1,435 mm) diameter driving wheels, in common with several other locomotives already in use on various railways, including the Bengal Nagpur Railway. Variant A, however, never saw production, and was excluded from the third edition of BESA's report in 1910.
From 1912, in common with other BESA designs, the HGS class was introduced, fitted with the Schmidtsuperheater - the S denotes superheated. The saturated HG locomotives that were later retrofitted with a superheater were given the classification of HGC - the C in the designation stands for converted. The superheated locomotives performed better than their saturated counterparts, as the latter were of British designs unsuited for the climate of the Indian subcontinent, due to their narrower fireboxes.
Pakistan Railways however, despite steam traction being mostly phased out in Pakistan in the 1990s, retained HGS 2216, 2277, and 2306 for use on the Khyber Pass Railway, where two of them worked top and tail on tourist trains to Landi Kotal, until 2006, when the railway suspended operations after monsoon rains damaged the line.
Preservation
Two of the Indian HG class locomotives have been preserved:
"History of Steam: Broad Gauge". www.indiansteamrailwaysociety.in. Archived from the original on 2016-06-29. Retrieved 15 July 2024. ... and also the alternate 2-8-0 Heavy Goods design which never materialised.
"Steam Locomotives Classes: Steam Locomotives". irfca.org. Retrieved 15 July 2024. Some locomotives were also converted from saturated to superheated to better perform in Indian conditions.