New Zealand DI class locomotive

The New Zealand DI class locomotive[nb 1] was a class of diesel-electric locomotive in New Zealand. They were built by English Electric in Australia.[1] The class is very similar to the Queensland Railways 1620 class locomotives.[2][3][4] At the time of their introduction, the class was seen as an alternative to the DB class for use on lightly laid secondary and branch lines, more so in the South Island, however the World Bank financed introduction of the Japanese built DJ class in 1968 ensured that no further DI class locomotives were purchased by New Zealand Railways.[3]

New Zealand DI Class
DI 1102 in Waipara in 2018.
Type and origin
Power typeDiesel-Electric
BuilderEnglish Electric
Rocklea works, Queensland, Australia
Build date1966
Specifications
Configuration:
​
 • UICCo-Co
Gauge1,067 mm (3 ft 6 in)
Wheel diameter3 ft 1 1⁄2 in (0.953 m)
Minimum curve330 ft (100.584 m)
Wheelbase33 ft 6 in (10.211 m) total, 11 ft 6 in (3.505 m) bogie
Length42 ft (12.802 m) over headstocks
Width8 ft 6 in (2.591 m)
Height11 ft 8 1⁄2 in (3.569 m)
Axle load10 1⁄2 long tons (10.7 t; 11.8 short tons)
Loco weight63 long tons (64.0 t; 70.6 short tons)
Fuel typeDiesel
Fuel capacity500 imp gal (600 US gal; 2,300 L)
Prime moverEnglish Electric 6CSRKT Mk II
RPM range450 - 850 rpm
Engine typefour stroke, four valves per cylinder
Aspirationturbocharged, intercooled
GeneratorEE827/9A
Traction motorsSix EE540/1A
Cylinders6 Inline
Cylinder size10 in × 12 in (254 mm × 305 mm)
MU working110V, ten notch
Loco brakeAir, dynamic
Train brakesAir
Performance figures
Maximum speed60 miles per hour (97 km/h)
Power output1,012 hp (750 kW) gross, 928 hp (690 kW) net
Tractive effort29,500 lbf (131.2 kN) at 9 mph (10 km/h)
Career
Number in class5
Numbers1100 - 1104 (original)
1808 - 1843 (TMS)
LocaleAll of New Zealand
First runApril 1966
Last runMay 1989
Disposition4 scrapped
1 preserved

Service

Three members of the class originally operated in the South Island, mainly on the Main North Line between Christchurch and Picton, while the other two members started life in the upper North Island.[3] In May 1969, all members were transferred to work in the Bay of Plenty area on the lightly laid track there.[3]

After the Kaimai Tunnel opened in 1978, all five members were transferred to the South Island for service in the Dunedin area. The class performed sterling service on the hilly Dunedin - Palmerston section of the Main South Line, and were also used to haul the Makareao branchline stone trains to Makareao due to their full adhesion Co-Co wheelset arrangement.[3] Members of the class occasionally made trips to Invercargill and were sometimes used on the Otago Central Line.[3]

Renumbering

In 1979 the computerised Traffic Monitoring System (TMS) was introduced, and the locomotives were renumbered as 1808, 1844, 1820, 1837 and 1843 respectively.[4]

South Island

They remained in Dunedin until 1984 - 1986, when they went north to Wellington and Napier mainly being used for shunting duties.[3] The locomotives were also used on revenue and special passenger services over the years of their operation.[3]

Disposal

Withdrawals

The first withdrawn from service was DI 1837 in January 1986 due to a fractured piston that had caused major engine damage, moving to Hutt Workshops late February 1987 for storage.[3] 1808 and 1814 were then laid up in April 1988. DI 1843 was withdrawn in May 1988 after a collision with a milk tanker truck in a level crossing accident near Otaki. 1808 was subsequently returned to service to replace 1843, until it suffered a major main generator failure in April 1989.[3] The remaining member of the class in service, 1820, was withdrawn in May 1989.[3] DIs 1814, 1837 and 1843 were scrapped at Hutt Workshops in March 1989, while 1808 was stripped of useful components in May 1991 by the Diesel Traction Group for spares for 1820.[3]

Preservation

DI 1820 was purchased by the Diesel Traction Group in 1989, and transferred to their base at the Ferrymead Heritage Park in September 1992.[3][5] The locomotive was restored from 2009 to 2018, and has since been renumbered back to DI 1102.[6] It was mainline certified in September 2018.[7][8][9]

Footnotes
  1. Following the introduction of TMS in 1979, the class classification was capitalised, whereas previously the second letter was a smaller capital letter, that is DI

References
  1. Diesels for NZ Railways Network March 1965 page 3
  2. Australian-built Diesel Locomotives for NZR Railway Transportation May 1966 page 6
  3. "Railfan". 6 (4). Triple M Publications. September 2000. ISSN 1173-2229. Cite journal requires |journal= (help)
  4. The 1620 Class Diesel-electric Locomotives Sunshine Express issue 588 September 2019 page 92
  5. Diesel group celebrates milestone with load test Narrow Gauge World issue 127 January 2018 page 15
  6. "Railfan". 24 (3). Triple M Publications. June 2018. ISSN 1173-2229. Cite journal requires |journal= (help)
  7. "Our Operating Partners". Diesel Traction Group. Retrieved 20 July 2018.
  8. "Diesel Locomotives". New Zealand Rolling Stock Register. Retrieved 20 July 2018.
  9. New Zealand diesel preservation progress The Railway Magazine issue 1422 September 2019 page 97

Bibliography
  • McGavin, T A (1983). NZR Locomotives and Railcars 1983. Wellington, New Zealand: New Zealand Railway and Locomotive Society.
  • McClare, E J (1980). New Zealand Railway Diesels. Wellington, New Zealand: Southern Press. ISBN 9780907769286.
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