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
Otford railway tunnel 8 original tunnels on the Illawarra line from Waterfall to Clifton. The Otford Railway Tunnel, the seventh after Waterfall, was the final major engineering project which permitted the linking up of the northern part of the Illawarra Line to the isolated southern part in 1888. The Otford Railway Tunnel opened on 3 October 1888. The single line connection was made at (old) Stanwell Park Station (now bypassed by the 1915 Stanwell Park Deviation). The tunnel was built of brick arched form and when built was the largest and steepest (5,985 feet long - 1824m - and 1 in 40 gradient)