Editing Porirua (section)

===Rail===
The development of the rail through Porirua, part of the [[Kapiti Line]], has contributed significantly to the development of Porirua as a satellite city of Wellington. The [[Wellington and Manawatu Railway Company]] opened a railway line through [[Johnsonville, New Zealand|Johnsonville]] from Wellington to Porirua in 1885. The railway reached [[Longburn]] (south of Palmerston North) in 1886 to connect with the government's lines to Taranaki and Napier. With the acquisition of the company by the government in 1908, the line to Porirua and northward to Longburn became part of the [[North Island Main Trunk]] railway. The railway provided regular passenger services between Wellington and Porirua and linked Porirua to other North Island centres. A shunting service from Wellington delivered goods wagons to sidings at Porirua, Paremata, Plimmerton, and Pukerua Bay and brought timber for the construction of houses in the area.

The [[Tawa Flat deviation|Tawa Flat railway deviation]] providing [[double-track railway]] with [[double line automatic signalling]] as far as [[Tawa, New Zealand|Tawa]] opened to passenger services on 19 June 1937, reducing travel time for passenger trains from Wellington to Porirua by 15 minutes, to 27 minutes rather than 43 to 48 minutes.<ref>Murray, Bruce (2014). ''A History of Tawa''. Wellington: Tawa Historical Society. {{ISBN|978-0-473-25848-1}}.</ref><ref name= M&P>Murray, Bruce; Parsons, David (2008). ''Rails through the Valley: The story of the construction and use of the railway lines through Tawa''. Wellington: Tawa Historical Society. {{ISBN|978-0-473-14410-4}}.</ref>

During 1940, [[Centralized traffic control|Centralised Train Control]] (CTC), which allowed direct control of signals and train movements by Train Control in Wellington, was progressively installed on the single line sections of track north of Tawa, replacing [[Tyer's Electric Train Tablet|tablet working]] and allowing more efficient, flexible, and rapid control of train movements. CTC between Plimmerton and Paekākāriki applied from 25 February 1940, Paremata to Plimmerton from 30 June, and Tawa to Porirua from 4 December 1940.<ref>Heine, Richard W. (2000). ''Semaphore to CTC: Signalling and train working in New Zealand, 1863–1993''. Wellington: New Zealand Railway & Locomotive Society. {{ISBN|0-908573-76-6}}.</ref>

On 24 July 1940, the line through Porirua, from Wellington to Paekākāriki, was electrified, and double track completed from Plimmerton to South Junction, just north of Muri railway station. Electrification allowed the introduction of electric [[NZR ED class|ED class]] locomotives, first introduced in 1938 for use on this line, to haul passenger and goods trains. Electric locomotives eliminated the smoke nuisance in the tunnels on the line and allowed longer trains to run. [[NZR DM class|DM/D]] [[electric multiple unit]]s first ran to Porirua on 5 September 1949 and replaced the majority of locomotive-hauled passenger trains and allowed a more frequent and faster train service.<ref name= M&P /> The duplication of the line from Plimmerton to South Junction allowed a more frequent train service between Porirua and Paekākāriki.

Duplication of the track from Tawa to Porirua station opened on 15 December 1957. This completed double line automatic signalling from Wellington distant junction, just south of [[Kaiwharawhara railway station|Kaiwharawhara]], to Porirua, and eliminated CTC between Tawa and Porirua. This work and the provision of additional signals between Kaiwharawhara and Tawa, allowed close following of trains and more frequent and faster train services between Wellington and Porirua. During peak periods, many multiple unit trains were now terminated at Porirua and returned to Wellington to provide a more frequent service between Wellington and Porirua than was provided for stations north of Porirua.

Extension of the double track and automatic signalling continued with the Porirua to Mana section opened on 7 November 1960. The work involved harbour reclamation to construct a straight tack from Porirua to [[Papakōwhai]], just south of Paremata, eliminating the tight curves as the former railway followed the coastline, and creating three lagoons on the eastern side of the harbour. The central lagoon, now known as [[Aotea Lagoon]], remains but is reduced in size. From Paremata to Mana, the track was realigned to the West of the original track and a new double-track bridge was built across the entrance to the Pauatahanui Inlet. The original single-track railway bridge, built in 1885, was removed to allow room for the construction of a second road bridge in 2004.<ref name = bridges>{{cite news |first= Andrea |last= O'Neil|title= Paremata Bridge opens the Porirua coast to beach lovers – 150 years of news |date= 11 August 2015|publisher=Stuff |access-date= 1 January 2019 | url= https://www.stuff.co.nz/dominion-post/news/70998726/null}}</ref> The railway stations at Porirua, Paremata, and Dolly Varden were replaced with new stations, with Dolly Varden station renamed Mana.

Mana to Plimmerton double track and automatic signalling were completed on 16 October 1961, completing the double track and automatic signalling from Wellington to South Junction, and allowing more frequent train services north of Porirua station. Crossovers at Plimmerton allowed some trains to terminate at Plimmerton and return to Wellington during peak periods.

By 2016, the introduction of electric multiple units with more rapid acceleration, [[New Zealand EM class electric multiple unit|EM/ET]] class from 1982 and [[NZR FP class|Matangi FP]] class from 2010, had reduced rail travel time for stopping trains between Wellington and Porirua by another 6 minutes to 21 minutes, despite extra stops at Redwood, Linden, and Kenepuru which each add 48 seconds to the travel time. For non-stopping trains, the time had reduced to 17 minutes. Off-peak passenger services between Wellington and Porirua stations ran every thirty minutes, with more frequent services during peak periods and a less frequent during the night.<ref>metlink ''Kapity Train Line'' timetable effective from 20 January 2016</ref> From 15 July 2018, off-peak day services were increased to one every twenty minutes.<ref>metlink ''Kapity Train Line'' timetable effective from 15 July 2018</ref>