|An NZR photo of Dx 2615 in December 1975 at Marton upon its introduction - one possibly two Bedford trucks can be seen further down the platform.|
The locomotives were initially confined to the NIMT and the Marton - New Plymouth Line, due to their high axle loading, and a need for the extra power on these lines. The electrification of the central section of the North Island Main Trunk in 1988 saw DXs redistributed, including to the South Island.
Upon introduction, all the DXs were painted in "clockwork orange" livery as in the example above. Between 1977 and 1986 they were all repainted in the "fruit salad" livery - red, grey, and yellow, which most of the class wore until the end of the decade. This livery had the road numbers displayed on the sides of the locomotives in large white numbers. The first to be painted as such was DX 2612. Since then, members of the DX class have received liveries including "Cato Blue" (fruit salad with blue instead of red), "Bumble Bee" (black and yellow), "Corn Cob" (green and yellow) and KiwiRail (grey, orange, and yellow).
Only one has so far been written off, 2639 following a crash at Newmarket in March 1977, details of which are in the book Danger Ahead: NZ railway accidents in the modern era. Two have had a thorough rebuilding, now called DXR and the rest have had various other modifications including prime mover power output upgrades and are known as DXB or DXC..