The NZR

New Zealand Railways Department

The New Zealand Railways Department, NZR or NZGR and often known as the "Railways", was a government department charged with owning and maintaining New Zealand's railway infrastructure and operating the railway system. The Department was created in 1880 and was reformed in 1981 into the New...

 DJ class locomotive is a class of diesel-electric locomotive used in New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

. The class were purchased from Mitsubishi Heavy Industries

Mitsubishi Heavy Industries

, or MHI, is a Japanese company. It is one of the core companies of Mitsubishi Group.-History:In 1870 Yataro Iwasaki, the founder of Mitsubishi took a lease of Government-owned Nagasaki Shipyard. He named it Nagasaki Shipyard & Machinery Works, and started the shipbuilding business on a full scale...

 with a modernisation loan from the World Bank

World Bank

The World Bank is an international financial institution that provides loans to developing countries for capital programmes.The World Bank's official goal is the reduction of poverty...

 to replace steam locomotives in the South Island

South Island

The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...

, where most of the class members worked most of their lives.

They are the second class of locomotive in New Zealand to utilise the Bo-Bo-Bo

Bo-Bo-Bo

thumb|Italian articulated Bo-Bo-Bo [[FS Class E656|E656]] locomotive, [[Rome]], June 2, 2006.A Bo-Bo-Bo in UIC classification is a locomotive with three independent two-axle bogies with all axles powered...

 wheel arrangement

Wheel arrangement

In rail transport, a wheel arrangement is a system of classifying the way in which wheels are distributed beneath a locomotive.. Several notations exist to describe the wheel assemblies of a locomotive by type, position, and connections, with the adopted notations varying by country...

, the other classes being the EW class

NZR EW class

The NZR EW class locomotive was a class of electric locomotive used in Wellington, New Zealand. The classification 'EW' was due to their being electric locomotives allocated to Wellington.- Introduction :...

 and the EF class

NZR EF class

The NZR EF class is a class of 22 25 kV AC electric locomotives that operate on the North Island Main Trunk between Palmerston North and Te Rapa in New Zealand...

. In both cases, this wheel arrangement was used to provide a lower axle-load due to track conditions as well, particularly in the case of the DJs, a shorter wheelbase more suited to sharp curvature on secondary or tertiary routes.
The DJ class were purchased with a modernisation loan and were the class that enabled the withdrawal of the remaining steam locomotives in the South Island (where they worked most of their lives) where they joined the existing DG/DH

NZR DG class

The NZR DG and DH class locomotives were a class of diesel-electric locomotives used on New Zealand's national rail network, built by English Electric.- Introduction :...

 class locomotives.