New Zealand DX Class Locomotive - Rebuilds: DXR Class

Rebuilds: DXR Class

In 1993, New Zealand Rail Limited undertook a significant rebuilding of DX 5362 into the first of what was to be a new sub-class, the DXR. The DX had been stored out of service at Hutt Workshops since early in 1989 suffering a cracked frame, and therefore was an ideal candidate for the rebuilding programme. Work began to fit the locomotive with a new 3,300hp GE 7-FDL diesel engine, upgraded traction motors with a ratio of 5.17 to the then-standard DX ratio of 4.55, and a new design of "Universal Cab" with a shorter low hood and more angular appearance. The use of 'R' (like the DBR class) denotes that the new locomotive was a rebuilt DX.

The newly rebuilt DX received the number DXR 8007 when it entered service in 1993 along with the prototype DFT class rebuild, DFT 7008. Initially it was intended that New Zealand Rail would rebuild all of the DX class locomotives to DXR specifications similar to the programme of rebuilding of the DF class into the DFT class, but after the privatisation of New Zealand Rail Limited (renamed Tranz Rail in 1995) later in 1993, the new management decided not to undertake further DX class rebuilds. One locomotive was however rebuilt to these original DXR specifications during the Tranz Rail years, DX 5310 in 2001 for its return to service following its derailment at Pukehou while hauling the Bay Express in 1995. It did not though receive a new DXR style cab, so it retained its original DX classification until it was overhauled to DXC standards in 2010.

Following the purchase of Tranz Rail by Toll in 2003, the new management authorised the rebuild of DX 5235 - itself having been stored since being damaged in a collision in Christchurch in 2000 - which became DXR 8022. The new DXR featured minor differences in the carbody hood and a MkII version of the "Universal Cab" which was more boxy that the previous MkI variant as applied to DXR 8007. The new DXR rebuild was classified as DXR 8022 and entered service in late 2005. It was decided to rebuild DXR 8007 to match 8022 in the interests of standardisation, and so 8007 was again rebuilt at Hutt Workshops in 2006.

Upon each rebuild, GE classified 8022 (and reclassified 8007) as model C30-8Mi. In 2007, DXR 8022 was one of the locomotives involved in a biofuel trial using of a fuel mix of 5 per cent biodiesel and 95 per cent regular diesel over a period of six months. With the introduction of the DL class locomotives into service the two DXR's were transferred to the South Island, and are now used between Middleton and Picton.

At 2,420 kilowatts (3,250 hp), the DXR class was the most powerful class of diesel-electric locomotive ever operated in New Zealand, until the introduction of the DL class in 2010, which surpassed the DXR's power output with 2,700 kilowatts (3,600 hp). As rebuilt by New Zealand Rail, DXR 8007 was classified by GE as their model C30-7M, while both 8007 and 8022 as rebuilt by Toll Rail are classified as model C30-8i.