Purewa Tunnel

Railway Tunnel in Auckland

Purewa Tunnel

The eastern tunnel portal from the air, looking west

Overview
Line| North Island Main Trunk railway
Location| Saint Johns
Status| Open
System| New Zealand Railways
No. of stations| None
Operation
Opened| 1 September 1929
Operator| KiwiRail
Character| Passenger/freight
Technical
Line length| 1,954 ft (596 m)[1]
No. of tracks| Double
Track gauge| 3 ft 6 in (1,067 mm)
Electrified| 2016

Purewa Tunnel is a 596-metre-long (1,955 ft) rail tunnel in Auckland, New Zealand.[2] It is on the North Island Main Trunk line and is located in the suburb of Saint Johns, to the west of Glen Innes. The tunnel is concrete-lined. Eastern Line passenger services operate through it,[3][4] and it is also used by the Northern Explorer and freight services.

## Background

[edit]

Proposals were made as early as the 1870s to re-route the Auckland–Westfield section of the North Island Main Trunk via a new eastern route through Glen Innes. Referred to as the Westfield Deviation, this was an easier grade than the NIMT's relatively steep uphill grade from central Auckland to Newmarket and Remuera.[5] By the 1920s, increasing traffic and delays between Auckland and Newmarket made the new route necessary.

## Construction

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The tunnel was started in March 1925[6] by workers experienced in the 'hard school... [of] the notorious railway tunnels of North Auckland' (i.e. constructing the North Auckland Line). With the assistance of horse-driven carts, the mining workers, mostly British (with some Italians and Dalmatians in the groups preparing the approach cuttings), were reported to have made good progress, working in triple shifts, using gelignite emplaced in drill holes to fracture the rock.[7][8]

The tunnel, while lit by electric lights during the excavation, was described as hosting a large number of glowworms, giving it a 'weird and fantastical' appeal.[8] Miners reported that the worms, likely to have entered from the nearby bush-clad gullies, were unlike anything they had ever reported in a working tunnel.[4] Further, the tunnel was also strangely attractive to a large number of sparrows that came to populate it, living from pilfered horse feed and becoming quite inured to the regular explosions.[8]

Break through was in April 1926[9] and the tunnel was completed in March 1928.[1] The Westfield Deviation, including the tunnel, opened for goods traffic on 1 September 1929, using the down line to Westfield Junction for single-line working, but was not used for passenger traffic until the up line to Auckland was opened on 11 May 1930.[10][11]

## Later work

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Purewa Tunnel eastern portal in 2019

The tunnel has in the past experienced some significant water drainage issues, which have required remedial work, and the installation of speed restrictions.[12] In 2010/2011, tracks within the tunnel were lowered to allow the required clearance for the Auckland railway electrification project.[3]

## External links

[edit]

* Photo of western approach construction - Auckland Weekly News 7 May 1925
* "Tunnel portal (photo)". New Zealand Herald (Papers Past). 23 April 1926.
* "Tunnel portal (photo)". New Zealand Herald (Papers Past). 24 April 1928.
* 2014 You Tube video of diesel trains

## References

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1. ^ a b "Underground Toilers, AUCKLAND STAR". paperspast.natlib.govt.nz. 26 March 1928. Retrieved 8 December 2019.
2. ^ New Zealand Railway and Tramway Atlas (Fourth ed.). Quail Map Co. 1993. ISBN 0-900609-92-3.
3. ^ a b Dearnaley, Mathew (10 January 2011). "Trains back on track after two week shutdown". The New Zealand Herald. Retrieved 10 January 2011.
4. ^ a b "Glowworms in a Tunnel". The Evening Post. 6 November 1926. p. 8. Retrieved 10 January 2011.
5. ^ "The Westfield Deviation". The New Zealand Railways Magazine – archived at Victoria University of Wellington. 1 February 1931. Retrieved 25 December 2018.
6. ^ "THE RAILWAY DEVIATION. AUCKLAND STAR". paperspast.natlib.govt.nz. 6 March 1925. Retrieved 8 December 2019.
7. ^ "Good Progress - Auckland Railway Deviation". The Evening Post. 12 February 1926. p. 8. Retrieved 10 January 2011.
8. ^ a b c "Sparrows In Tunnel". The Evening Post. 2 July 1927. p. 8. Retrieved 10 January 2011.
9. ^ "Purewa Tunnel Pierced, NEW ZEALAND HERALD". paperspast.natlib.govt.nz. 26 April 1926. Retrieved 8 December 2019.
10. ^ AJHR 1930 D1 page xvii
11. ^ Pierre, Bill (1981). North Island Main Trunk. Wellington: Reed. p. 178\. ISBN 0-589-01316-5.
12. ^ "Monthly Business Report" (PDF). Auckland Regional Transport Authority. July 2010. Archived from the original (PDF) on 24 July 2011. Retrieved 10 January 2011.

36°52′16.61″S 174°50′54.4″E﻿ / ﻿36.8712806°S 174.848444°E﻿ / -36.8712806; 174.848444
*[No.]: Number