Southern Line (Auckland)
The Southern Line in Auckland, New Zealand, is the name given to suburban train services that operate between Waitematā and Pukekohe via Newmarket. Services are operated by Auckland One Rail under the Auckland Transport brand.
Routing
From Waitematā to Newmarket, Southern Line services use the Newmarket Line, then follow the North Auckland Line to Westfield Junction, and thence onto the North Island Main Trunk line as far as Pukekohe, the terminus of the Southern Line. In its entirety, this line follows the original 1875 North Island Main Trunk route between central Auckland and Pukekohe.The line, originally single-tracked, was duplicated, piecemeal, between 1909 and 1939. In 1915, the original single-track Parnell tunnel was bypassed by a twin-track tunnel. The older tunnel can be seen alongside the current one, between Parnell station and Newmarket Junction.
History
In 1930, the Westfield Deviation opened a new eastern route for the NIMT between Auckland and Westfield via Glen Innes. The route between Auckland and Westfield via Newmarket then ceased to be part of the NIMT. The portion between Newmarket and Westfield became part of the North Auckland Line, which runs between Westfield and Whangārei.The Southern Line suburban services continued to run on the older route. A new line, called the Eastern Line, was introduced for services on the new route. While the Eastern and Southern lines have a different route between Auckland and Westfield, they share the same tracks between Westfield and Puhinui station.
Third Main Line
Construction for the third main line, as part of the Wiri to Quay Park began in 2020 and was completed by 2025. It is expected to ease congestion on Auckland rail lines by allowing "through" trains to pass stationary trains at stations, improve rail freight access from the Port of Auckland to the Westfield yards and allow more frequent passenger and freight services. The new line runs between Westfield Junction and just south of Wiri Depot.These improvements will avoid an estimated 175,000 annual freight movements on the state highway network. Work began at the end of 2020. The $315 million funding package for these works was announced as part of the Government's New Zealand Upgrade Programme.