In 1964 Commonwealth Railways ordered three locomotives from Tulloch Limited based on a Sulzer design that had entered service with the Nigerian Railway Corporation. The first was handed over on 12 May 1965 and named after Federal Minister for Shipping & Transport Gordon Freeth. In 1966 a further three were delivered for the North Australia Railway. A further seven were delivered in 1968, two for the Central Australian Railway and five for the North Australia Railway. Following the delivery of the NJ class in 1971, all the five Central Australian units were transferred north. In November 1972 three were destroyed in a runaway at Frances Bay freight yard. Following the closure of the North Australia Railway in December 1974, the remaining 10 NTs were transferred to the Central Australian Railway. In July 1975 all were included in the transfer of Commonwealth Railways to Australian National. Following the closure of the narrow gauge Central Australian Railway in 1980, three were transferred to the Eyre Peninsula Railway with the others withdrawn. The last three were withdrawn in the late 1980s with NTs 69 and 73 going out in a blaze of glory, when, during their scrapping, they caught fire.
NT65 - Named Gordon Freeth; Delivered 24 April 1965; First NT to work over the Quorn line on its delivery 1 May 1965 To Northern Australia Railway 13 September 1971: To Central Australia Railway 1976; Stored Port Augusta 1981; 575,954 km
NT66 - Delivered 18 June 1965 via Broken Hill and Quorn; to NAR 4 October 1971; to CAR 1976; Stored Port Augusta 1981; 948,205 km
NT67 - Delivered 4 August 1965 via Quorn line ; To NAR 14 February 1968; To CAR 1976 - used as Marree Narrow Gauge Shunter; Stored Port Augusta 1981; To Peterborough 1 February 1983 To Wilmington Line ~August 1984 - scrapped Gladstone 1989
NT68 - Delivered 11 November 1966; To NAR 5 December 1966; Involved in major accident Darwin Yard 4 November 1972; To CAR 1975; Withdrawn at Port Augusta 1978.
NT69 - Delivered 28 November 1966 via Quorn Line ; To NAR 20 December 1966; to CAR 1976; Stored Port Augusta 1981; To Peterborough 1 February 1983; Last North Australia South and North Bound trains 29/30 June 1976; to Port Lincoln 1984 - First to be repainted AN Corporate green and gold January 1985 following "rough" overhaul; Last mainline train from Rudall 11 April 1988. Last operated 21 June 1988 as Port Lincoln yard shunter Scrapped Port Lincoln 21 August 1990
NT70 - Delivered 11 January 1967; to NAR 23 June 1967; Involved in major accident Darwin Yard 4 November 1972; Scrapped 1975
NT71 - Delivered 1 February 1968 via Quorn Line ; To NAR 2 May 1968;Involved in major accident Darwin Yard 4 November 1972; Scrapped 1975
NT72 - Delivered 21 March 1968 via Quorn Line ; To NAR 1 July 1968; to CAR 1976; Scrapped in 1978
NT73 - Delivered 18 April 1968; to NAR 1 July 1968; to CAR 1976; To Gladstone 16 October 1981; to Port Lincoln ~February 1985 - repainted AN Corporate green and gold February 1985 following complete engine overhaul; Last mainline train from Rudall 11 April 1988; Last operated Port Lincoln 21 September 1988 as yard shunter Scrapped Port Lincoln 21 August 1990
NT74 - Delivered 1 June 1968;to NAR 18 January 1971;to CAR 1976;To Peterborough 13 November 1981; Used to recover Quorn Line Assets; To Port Lincoln ?1984. Rewired Port Lincoln Workshops; stored following crankshaft failure at 28 July 1987 Scrapped Port Lincoln November 1989.
NT75 - Delivered 28 June 1969; to NAR 27 August 1968; Involved in major accident Darwin Yard 4 November 1972 to CAR 1975 - Scrapped Port Augusta 1975
NT76 - Delivered 12 August 1968; To NAR 1 November 1968; to CAR 1976; Last movement on CAR-Marree Yard Shunter 27 March 1980 to Gladstone 5 April 1980; First trip to Booleroo Centre with NSU56 9 April 1980; Used as trailing unit pending sound proofing: withdrawn from service 1986 transferred to Wilmington line ~1986 - Operational - Pichi Richi Railway
NT77 - Delivered 25 September 1968; To NAR 5 August 1971; to CAR 1976 Scrapped Port Augusta 1976
