Hutt Valley Line - Extension and Electrification

Extension and Electrification

After World War II, the Hutt Valley experienced significant population growth, and extension of the Hutt Valley Branch to Taita was approved. Already built to Waterloo as double track, the next section to Naenae opened on 7 January 1946 initially as single track. On 14 April 1947 the line to Taita opened, and the section from Waterloo to Naenae double tracked. The section from Naenae to Taita was duplicated on 22 February 1953. A proposal to extend the Taita line to link up with the original Hutt Valley main line had been approved in February 1946, and in the early 1950s this was carried out. On 28 February 1954, the section of the old main line between Melling and Haywards (now Manor Park) closed, leaving the Lower Hutt to Melling section as the Melling Branch. On 1 March 1954 the new Taita to Haywards section opened and the Hutt Valley Branch was incorporated into the Wairarapa Line. Initially single track, the section was duplicated on 19 July 1954.

Electrification had been approved in response to post-WWII coal shortages and was also implemented in the 1950s, with the first electrified section opened on 14 September 1953 from Kaiwharawhara to Taita. The old bridge over the Hutt River to Silverstream was found unsuitable for electrification and a deviation was built to the north over a new bridge. A direct line from Taita to Silverstream through the Taita Gorge with a tunnel had been proposed, eliminating the route across the river to Haywards and then back over at Silverstream, but the soil through the gorge was found unsuitable, and two bridges were built instead. Some of the original line replaced by the new route to Silverstream has been preserved by the Silver Stream Railway.

On 19 July 1954, the railway was duplicated to a point north of Haywards, and on 21 November a single track on the new Silverstream deviation was brought into use. Duplication from Haywards was completed to Trentham on 26 June 1955. On 24 July the electrification was completed to Upper Hutt and diesel-hauled suburban passenger trains north of Taita ceased.

On 3 November 1955 the Rimutaka Incline was replaced by the Rimutaka Tunnel, speeding travel from the Hutt Valley to the Wairarapa. This involved re-routing the Wairarapa Line north of Upper Hutt. The Kaitoke route via Kaitoke and Summit in the Rimutaka Ranges at the western end of the incline was closed and replaced by a line through Maymorn to the tunnel.

The 2009-2011 upgrading of passenger lines in the Wellington region included new power substations at Lower Hutt, Woburn and Silverstream.