New Zealand DF class locomotive (1979)

New Zealand DF / DFT class (General Motors)

DFT 7295 departing the Ashburton yard, 20 February 2013. Note the enlarged driver's side windscreen.

Type and origin Power type Diesel-electric Builder General Motors Diesel (GMD), Canada (builder) Tranz Rail (rebuilder) Model DF EMD GL22MC DFT EMD GT22MC Build date 1979 - 1981 1992 - 1997 (rebuilt as DFT class)

Specifications UIC class Co-Co Gauge 3 ft 6 in (1,067 mm) Length 16.7 metres (54 ft 9 in) Adhesive weight 86 tonnes (85 long tons; 95 short tons) Loco weight 86 tonnes (85 long tons; 95 short tons) Prime mover GM 12-645E (DF) GM 12-645E3C (DFT) RPM range 900 rpm Engine type V12 Diesel engine Aspiration Roots-type supercharger (DF) Turbocharger (DFT) Displacement 126.84 litres (7,740 cu in) Traction motors Six D29cc Cylinders 12 Cylinder size 230 mm × 254 mm (9.1 in × 10.0 in)

Performance figures Maximum speed 113 km/h (70 mph) Power output 1,230 kW (1,650 hp) DF 1,800 kW (2,400 hp) DFT Tractive effort 198 kN (45,000 lbf)

Career Number in class 30 (14 DFBs and 16 DFTs) Numbers 1651 - 1670 (original DF) 6006 - 6317 (TMS DF) 7008 - 7348 (DFT) Locale All of New Zealand First run 1979 Disposition 9 DFTs in service 14 DFBs in service 3 DFTs undergoing overhaul to DFB 4 DFTs withdrawn

The New Zealand DF class locomotive of 1979 is a class of 30 Co-Co diesel-electric locomotives built by General Motors Diesel of Canada between 1979 and 1981. Between 1992 and 1997, all the locomotives were rebuilt as the DFT class, a turbocharged version of the DF.

The class should not be confused with the English Electric NZR DF class of 1954; as all of the old DFs had been retired by mid-1975, the 'DF' classification was free to be re-used.

The DFs were powered by an EMD 12-645 engine, the same prime mover chosen for the DC class, but were able to make greater use of that power by having six traction motors and Co-Co arrangement as opposed to the four traction motors and A1A-A1A wheel arrangement of the DCs. This gave the DF several advantages: a tractive effort of 198 kN (45,000 lb_f) and a maximum speed of 113 km/h (70 mph), compared to the DCs 140 kN (31,000 lb_f) and 90–100 km/h (56–62 mph). The most noticeable visual difference between the DF and the DC is that the DF is considerably longer with the headlight arrangement on the cabs differing: the DC has the lights arranged horizontally, while the DF has them arranged vertically. The DF is more often confused with the DX class, as both are of similar dimensions though the DX also has the horizontal headlight arrangement.

The first 20 members of the DF class arrived in New Zealand in 1979, and initially ten worked on the East Coast Main Trunk, Kinleith, Rotorua and Murupara Branches, making use of the recently opened Kaimai Tunnel; and ten worked freight trains on the Main North Line between Christchurch and Picton. At the time, they were the most powerful locomotives in the South Island, with a total power output of 1,230 kilowatts (1,650 hp).