NZR DF class (1979)

NZR DF / DFT class (General Motors)
DFT 7145 in Ahuriri Yard, Napier - 8 June 2003. Photo by Joseph Christianson. DFT 7295 in Dunedin in former Tranz Rail "Bumble Bee" colours.
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)
UIC classification	Co-Co
Gauge	1,067 mm (3 ft 6 in) Cape gauge
Length	16.7 metres (55 ft)
Weight on drivers	86 tonnes (85 long tons; 95 short tons)
Locomotive weight	86 tonnes (85 long tons; 95 short tons)
Prime mover	GM 12-645
Engine RPM range	900 rpm
Aspiration	Roots blower (DF) Turbocharger (DFT)
Displacement	126.84 litres (7,740 cu in)
Traction motors	Six D29cc
Cylinders	V12
Cylinder size	230 mm × 254 mm (9.1 in × 10.0 in)
Top 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)
Number in class	30
Number	1651 - 1670[n 1] (original DF) 6006 - 6317 (TMS DF) 7008 - 7348 (DFT)
Locale	All of New Zealand
First run	1978
Disposition	In service

The NZR DF class 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 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.

Introduction

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, 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).

The next ten DFs arrived in 1981 and were also sent to work in the Bay of Plenty, and some to supplement the South Island fleet, which by this time had also entered service on the Main South Line and Midland Line as far as Arthur's Pass.

In 1986 the DF fleet was reallocated, concentrating 22 of the class in the South Island, and reallocating the remaining eight North Island DFs from Hamilton to Wellington, for use between Wellington and Gisborne, on the Wairarapa Line and Palmerston North - Gisborne Line (PNGL).

In 1988, the fleet was again reallocated due to the opening of the NIMT electrification, with approximately 20 DFs based in Auckland for use in Northland and between Auckland and Tauranga and the remaining units based in the South Island. This reduced the DFs from the lower North Island - Gisborne routes, and the reduced the number in the South Island. Being such handy units this class sees far more inter-island transfers than the other classes. The allocations in the class register below can only be taken as a guide.

Like the DCs, the DFs were powered by an EMD 12-645 engine, delivering the same power output, but were able to make greater use of that power by having six traction motors, unlike the four traction motors of the DCs with their A1A-A1A wheel arrangement. The Co-Co wheel arrangement had several advantages: it gave the DF a tractive effort of 198 kN (45,000 lb_f) and a maximum speed of 113 km/h (70 mph), compared to the DC's 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 was the headlight arrangement on the cab: the DC had the lights arranged horizontally, while the DF had them arranged vertically. The DF is also considerably longer than a DC.

Upgrades

The locos received an upgrade in the late 1980s to improve visibility for the driver - this involved a large single front window replacing the original configuration that had two small windows instead.

Rebuilding to DFT

The main downside to the DF was the lack of power output from the diesel engine. This hindered the DF when it came to haulling heavy freight trains out of multiple.

In 1992, DF 6260 was rebuilt with a new turbocharged diesel engine and some other minor alterations. The rebuilt DF was reclassified DFT (the T standing for turbocharged), and was renumbered 7008.

After 18 months of trial, the remaining 29 DF were converted to DFTs, with the last converted in 1997. The turbocharged locos can now generate 1,800 kW (2,400 hp), and now comfortably fits between the DC class and the DX class in terms of power output.

Sub-classes

DFTs fitted with Maxitrax wheelslip control received an internal sub-classification of DFM in the early 2000's. This was an internal designation only, used in the Amicus computer system, and the classification was not applied to the locomotives themselves which remained officially classified as DFT. Maxitrax has since been removed from all of these locomotives.

In 2006 Toll Rail began installing the Brightstar engine management system into a number of DFT class locomotives. These locomotives were then officially reclassified as DFB.

ARTA service

DFB 7010 at Morningside station with a 6-car SA set

Four DFTs/DFBs are currently in service in Auckland hauling six car SA trains on the Auckland suburban network. These trains are made up of ex-British Rail Mark 2 carriages, rebuilt for use on Auckland commuter trains. Most are currently in four or five car configurations with a DC class locomotive. The four locomotives currently in service on 6 car SA sets are DFB 7010, DFB 7348, DFB 7200 and DFT 7104. These began service on 20 September 2010 with the introduction of a new timetable.

Class register

Key:	In service	Out of service	Auckland Transport service	Preserved	Overhaul	Scrapped

TMS No. (DFT)	TMS No. (DF)	Original No.[n 1]	Introduced	Current Livery[n 2] [n 3]	Status	Allocated to	Notes
DFT 7008	DF 6260			KiwiRail	In service	North Island	First DFT rebuild. Damaged after hitting a truck near Temuka, March 2008. Repaired & received KiwiRail livery.
DFB 7010	DF 6300			MAXX Blue	In service	North Island
DFT 7023	DF 6248			Toll Rail ("Corn Cob")	In service	North Island
DFM 7036	DF 6317			Tranz Rail Blue	In service	North Island
DFT 7049	DF 6219			Tranz Rail Black ("Bumble Bee")	In service	North Island
DFT 7051	DF 6231			KiwiRail	In service	North Island
DFT 7064	DF 6254			Tranz Rail Blue	In service	North Island
DFT 7077	DF 6225			Tranz Rail Black ("Bumble Bee")	In service	North Island
DFM 7092	DF 6283			Tranz Rail Blue	In service	North Island
DFT 7104	DF 6277			MAXX Blue	In service	North Island
DFT 7117	DF 6156	DF 1665		Tranz Rail Blue	Under overhaul	South Island	Out of service after running into a landslide near Kaikoura on 21 June 2011[2]
DFT 7132	DF 6191	DF 1669		KiwiRail	In service	South Island
DFM 7145	DF 6012	DF 1652	01979-10 October 1979	KiwiRail	In service	South Island
DFB 7158	DF 6202	DF 1670		KiwiRail	In service	North Island
DFB 7160	DF 6087	DF 1659		KiwiRail	In service	North Island
DFB 7173	DF 6029	DF 1653	01979-09 September 1979	Tranz Rail Blue	In service	North Island
DFB 7186	DF 6070	DF 1658		KiwiRail	In service	North Island
DFT 7199	DF 6110	DF 1662		Tranz Rail Blue	In service	South Island
DFB 7200	DF 6185	DF 1668		MAXX Blue	In service	North Island
DFB 7213	DF 6104	DF 1661		Tranz Rail Blue	In service	North Island
DFM 7226	DF 6035	DF 1654		KiwiRail	In service	South Island
DFB 7239	DF 6006	DF 1651	01979-10 October 1979	KiwiRail	In service	North Island
DFB 7241	DF 6093	DF 1660		Tranz Rail Blue	In service	North Island
DFB 7267	DF 6179	DF 1667		KiwiRail	In service	North Island
DFT 7282	DF 6041	DF 1655		Tranz Rail Black ("Bumble Bee")	In service	North Island
DFT 7295	DF 6127	DF 1663		Tranz Rail Black ("Bumble Bee")	In service	South Island
DFB 7307	DF 6133	DF 1664		Toll Rail ("Corn Cob")	In service	North Island	Tasman Forestry livery November 1991 - DFT rebuild.
DFM 7322	DF 6162	DF 1666		Tranz Rail Blue	In service	North Island
DFM 7335	DF 6064	DF 1657		Tranz Rail Blue	In service	North Island
DFB 7348	DF 6058	DF 1656		MAXX Blue	In service	North Island	Formerly DFT 7254. Renumbered when returned to service after involvement in a fatal collision at Waipahi in 1999

1. ^ ^{a b} Ten locomotives never received road numbers, as they began service after the introduction of TMS in 1980.
2. ^ Livery is from latest information posted on New Zealand Railtrack.^[1]
3. ^ DFTs due to receive a KiwiRail repaint include DFT 7023, DFB 7173, DFT 7199, DFB 7213 and DFB 7307.

References

• "NZR Locomotives and Railcars 1983". T A McGavin. New Zealand Railway and Locomotive Society : Wellington, New Zealand : 1983.
• "New Zealand Railway Diesels". E J McClare. Southern Press : Wellington, New Zealand.

Footnotes

1. ^ "New Zealand RailTrack". http://www.quicktrip.co.nz/rails/railtrack.htm. Retrieved 2010-10-03. 
2. ^ "Freight train slips off track". stuff.co.nz. http://www.stuff.co.nz/marlborough-express/news/5170818/Freight-train-slips-off-track. Retrieved 25 June 2011. 

See also

• List of GMD Locomotives