By 1877 the main lines in New South Wales were nearing Tamworth, Wagga Wagga and Orange. The additional distances required an increase in motive power, especially as at that time, locomotives were changed after quite short journeys. They were only in service when manned by their regular crew. Between 1877 and 1881, the initial order of 50 of these 0-6-0wheel arrangement locomotives were delivered from Beyer, Peacock and Company. Between 1880 and 1891, Beyer, Peacock delivered a further nine and local manufacturer, Henry Vale and Company eighteen. The load which these locomotives could haul over the Blue Mountains line was 128 tonnes at 11–13 km/h. William Thow, the then Locomotive Engineer of the South Australian Railways, was commissioned by the New South Wales Government in 1888 to enquire into the New South Wales Government Railways locomotives and rolling stock. He recommended modifications to this class as he considered them to be the best designed and proportioned of the locomotives then in service. This included Belpaire boilers and new cabs. Following the reclassification of locomotives in 1891, three additional similar locomotives were added to the class. With the arrival of the T class saw the class relegated to secondary roles and coal services in Newcastle. Between April 1902 and February 1910, fourteen were converted to 20 class 2-6-4 tank engines at Eveleigh Railway Workshops. By 1933 many had been withdrawn, with only 36 remaining in service. Having a short wheelbase and no leading bogie, the locomotives had a tendency to derail and they were ultimately restricted to a maximum speed of 40 km/h and relegated to shunting and branch line traffic. Driven slowly, they could negotiate the most appalling curves and badly maintained or unballasted tracks. They were therefore ideal in goods yards, such as Darling Harbour and Port Waratah with the last two withdrawn from the latter in August 1972. Branch lines such as those to Dorrigo, Batlow and Oberon where grades of up to 1 in 25 and curves as sharp as radius could be encountered were ideal for this class and these were the only locomotives permitted on these lines until dieselisation.
Preservation
Four locomotives of the class have been preserved:
