Rimutaka Tunnel the first fully dieselised line in New Zealand. Today, DBR, DC, DFT and DX class locomotives run the route. There have been proposals to electrify the tunnel and the Wairarapa line as far north as Masterton as an extension of the Wellington suburban electrification. The tunnel was designed to enable catenary to be installed but this has not happened, and the catenary finishes just north of Upper Hutt station. In 2007, Greater Wellington Regional Council rejected a call to electrify the tunnel, on the basis that patronage did not justify the expenditure, and that the tunnel would "have to be
Rimutaka Tunnel tunnel. Detailed surveys were completed in 1938/1939, but the project was again postponed due to World War II. After World War II it became a matter of urgency to consider a replacement. The H class locomotives were showing their age, the Incline was in bad shape, and maintenance costs were increasing. Between September 1945 and July 1947 four options were considered. It was accepted that no contour line could be the solution and that a tunnel under the Rimutaka Ranges was the only satisfactory answer. The adopted route was the shortest route, a tunnel between Mangaroa and Lucena’s Creek gully.