The New Zealand DI class locomotive was a class of diesel-electriclocomotive in New Zealand. They were built by English ElectricAustralia. The class is very similar to the Queensland Railways 1620 class locomotives. 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 IMF financed introduction of the Japanese built DJ class in 1968 ensured that no further DI class locomotives were purchased by the Railways Department.
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 North Island. In 1969, all members were transferred to work in the Bay of Plenty area on the lightly laid track there. 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 used to haul the Inch Valley branch line stone trains due to their full adhesion Co-Co wheel set arrangement. On occasions, members of the class made trips to Invercargill as the roster allocated and were used on the Otago Central Line as far as Ranfurly. They remained in Dunedin until 1984 – 1985, when they went north to Wellington and Napier. In their latter days the DI class was used mainly for shunting duties.
Withdrawal and preservation
In 1988, three members of the class were written off following accidents. The remaining two locomotives were withdrawn by 1989, following the conversion of the DSC class shunting locomotives to right-hand control.
DI 1104 was originally selected for preservation by the Diesel Traction Group. However during the late 1980s the engine was scrapped after following a collision with a truck at a level crossing. The DTG eventually led preserved 1102 instead for preservation, being the best one of the fleet. The locomotive is now under restoration at the Ferrymead Heritage Park and will be mainline certified.
