Rail works of recent years, such as the triangle north of Newmarket, have incorporated provision for electrification, such as base foundations. Recent bridge works have increased clearances for the catenary.The same junction as above in December 2010, with some of the traction poles in place, although as yet unfinished.
The Newmarket Line was originally opened in 1873 as the northern portion of Auckland's first railway to Onehunga via Penrose. It was part of the North Island Main Trunk Railway until the Westfield Deviation opened in 1930.[3]
Since 1915, it has been fully double tracked after an upgrade of Parnell Tunnel north of Newmarket. Previous to that, it led as a single track section through a previous Parnell Tunnel.[4]
In 2007, the major junction that connects the Newmarket Line with the North Auckland Line was rebuilt into a 'wye junction', removing the time-consuming reversing backshunt needed to access the NAL to the north from the Newmarket Line, thus giving the line better access to Waitematā Station. This was part of a big upgrade of rail infrastructure in Auckland, and the Newmarket Station and Junction was included in the stage one electrification of the network.
A new station, Parnell, began operation on the line at the suburb of the same name on 12 March 2017 to serve the Western and Southern Lines of the city's train network, with an official opening on 13 March.[5]
