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
Tunnel Railway Romney, Hythe and Dymchurch Railway. As the new railway would not be carrying heavy loads and would be travelling only a short distance, it was built as a narrow gauge railway, with a track gauge of . This allowed the new branch tunnel to be built to far smaller dimensions than the existing tunnel, at just high and wide. Although a cable haulage system had initially been considered, Ramsgate Olympia decided early in the line's planning to electrify the line. A third rail system was rejected due to concerns for the safety of the large numbers of children expected to