The new cab was designed in-house by NZR, who then took the unusual step of contracting NZR's Westport Workshops to build them on Hillside's behalf. The cab itself was larger than the original DG cab, which required the low nose at the front to be shortened. The whole assembly had a pronounced box-like shape, with 45° angles to the cab roof and low nose. The new cab featured four windscreens to the original three, while the low nose had a larger doorway to access the new Westinghouse 26L air-brake equipment and also gave provision for a short walkway on either side of the nose. The small windows were the same as used on the DX class locomotives to improve standardisation on locomotives.