|Stratford–Okahukura route map|
The Stratford-Okahukura Line (SOL) is a secondary railway line in the North Island of New Zealand, between the Marton - New Plymouth Line and the North Island Main Trunk Railway, with 15 intermediate stations. It is 144 km (89 mi) long through difficult country, with 24 tunnels, 91 bridges and a number of sections of 1 in 50 grade. Near Okahukura there is an unusual combined road-rail bridge over the Ongarue River, with the one-lane road carriageway below the single rail track. The line is not currently in service for rail traffic and is under a 30-year lease for a tourist venture.
The line from Stratford to Whangamomona (of about 48 miles) was authorised by the Railways Authorisation Act, 1900  The Hon William Hall-Jones turned the first sod of the Stratford-Kawakawa Railway at Stratford on 28 March 1901.
Kawakawa, south of Ongarue, was to be the junction point with the North Island Main Trunk Line. Construction took nearly 32 years, and the western part, from Stratford, was operated as the Toko Branch from 9 August 1902. The SOL was nearly complete before the onset of the Great Depression, so work was not halted, unlike on many public works projects such as the East Coast Main Trunk Railway beyond Taneatua.
The section from Okahukura to Matiere was officially opened on Tuesday 23 May 1922, although the bridges to the west of Tuhua were temporary rather than the final and stronger structures. At the opening ceremony, the Minister for Public Works, the Hon Gordon Coates (subsequently Prime Minister, 1925-1928) said the cost of building that segment of the line was £33,000 per mile. At the same time, a separate report indicates that the track had been laid from Stratford for 47 miles (76 km) up to Tahora, leaving a 31 mile (50 km) gap between Tahora and Matiere.
The Mayor of Stratford celebrated the piercing of the last tunnel (52.5 ch (3,460 ft; 1,060 m) No.4 Mangatiti) on 2 August 1932 and, on 7 November 1932, the last spike was driven at Heao by the Prime Minister, the Right Hon. George Forbes, with Rt. Hon. Gordon Coates driving the first train. Goods traffic started on 12 December 1932, though the SOL was not handed over by the Public Works Department to the New Zealand Railways Department until 3 September 1933.
Although generally understood to have trains operating, especially in the later years, on a warrant control basis, mention is made in the 1939 Railways Report to Parliament of the completion of automatic single-line signalling on the line. The final section was from Whangamomona to Okahukura, in those days a distance of 51 miles 52 chains (ie 83.1 km) and consistent with modern distance measurements.
1950s Upgrades and Maintenance
Upgrades and maintenance to the track were undertaken in 1959-60. Some of the track was replaced with 75 lbs/yd rail that at some point was made into a continuously welded rail.
Crossing loops were established at Te Wera, Whangamomona, Tangarakau and Ohura. Three stations (Te Wera, Whangamomona and Ohura) had stationmasters. The short loops meant that long trains had to be split to fit into the loop and siding.
The SOL was initially served by the New Plymouth Night Express between New Plymouth and Auckland and by Stratford–Taumarunui passenger trains. When the line opened, it was reported that overnight express trains between Auckland and New Plymouth could now complete the journey in less than 12 hours. Whangamomona had refreshment rooms from 1933 to 1965.
Scheduled passenger trains ceased in January 1983 as roads in the rugged and isolated northern Taranaki were improved and passengers switched to cars, though the line was not closed to all passenger trains until January 2007, after an excursion to Whangamomona's "Republic Day" celebrations. This terminated the operation of excursions, but efforts are underway to have the line upgraded to a standard where excursions will again be possible. A working party of stakeholders was formed in June 2007 to investigate the current state of the line and to develop a case for upgrading it. Considerable maintenance is required to bring the line up to safety standards required for passenger trains; this will cost approximately NZ$6 million to complete, according to Stratford Mayor Brian Jeffares.
Most freight was for the rural hinterland, but along the SOL there were coal mines near Ohura and Tangarakau, and also sawmills. One freight train operated each weeknight each way along the line carrying freight between New Plymouth and Auckland, interchanging at Taumarunui. In recent years the deferred maintenance issues meant these services operated under heavy speed restrictions.
The SOL was upgraded in 1959-60, and a deviation and a new station building built at Stratford.
In conjunction with the Marton - New Plymouth Line the SOL also provided an alternative route when the North Island Main Trunk was closed between Marton and Taumarunui. In 1953 the Tangiwai disaster closed the NIMT for a period.
The SOL suffered from a lack of investment on maintenance in recent years, leading to a number of speed restrictions being put in place. In July 2002 a fatal derailment occurred at Te Wera, and a number of other incidents also plagued operations. In November 2009 a serious partial derailment of a wagon occurred, damaging some 8 km of line preventing use by trains without repairs. (Note that KiwiRail describes the damage as covering 9.5 km of track.) Following this KiwiRail decided to mothball the 144 km line, with rail freight now being routed through Palmerston North. However, ideas for preserving the line emerged with hopes that customers and investment could be found to return the line to full service.
Adventure tourism operator Forgotten World Adventures reached agreement with KiwiRail in 2012 to lease the line for their new venture using modified petrol rail carts for tourists to travel between the line's termini at Stratford and Okahukura, via a number of trip options, starting from Labour Weekend 2012. The 30-year lease makes the company responsible for the line's maintenance and access control but allows KiwiRail to use the line in emergencies and to resume control of the line depending on future circumstances and opportunities. The rail bridge over State Highway 4 at Okahakura has been removed making the track between the eastern most tunnel and Okahakura unusable. 
- See Alexander, R. B., "The Stratford-Okahukura Line," at pp. 8-22 for a detailed description of the difficult construction (2nd revised edition, 1983, New Zealand Railway & Locomotive Society).
- Google Streetview showing combined road and rail bridge
- "Railways Authorisation Act, 1900". New Zealand Law online.
- "MESSAGES OF GOODWILL (Stratford Evening Post, 1932-11-07)". paperspast.natlib.govt.nz. Retrieved 13 January 2018.
- https://paperspast.natlib.govt.nz/newspapers/NZH19220524.2.85 NZ Herald, 24 May 1922
- https://paperspast.natlib.govt.nz/newspapers/AS19220523.2.65 Auckland Star 23 May 1922
- "ANOTHER STEP IN BUILDING EAST LINE (Stratford Evening Post, 1932-08-03)". paperspast.natlib.govt.nz. Retrieved 13 January 2018.
- "THROUGH TRAFFIC (Evening Post, 1932-11-07)". paperspast.natlib.govt.nz. Retrieved 13 January 2018.
- "LAST SPIKE DRIVEN. (Horowhenua Chronicle, 1932-11-07)". paperspast.natlib.govt.nz. Retrieved 14 January 2018.
- "STRATFORD RAILWAY (New Zealand Herald, 1932-12-09)". paperspast.natlib.govt.nz. Retrieved 13 January 2018.
- "Appendix to the Journals of the House of Representatives 1935 Session PUBLIC WORKS STATEMENT (BY THE HON. J. BITCHENER, MINISTER OF PUBLIC WORKS)". paperspast.natlib.govt.nz. Retrieved 13 January 2018.
- https://paperspast.natlib.govt.nz/parliamentary/AJHR1940-I.184.108.40.206/2 See page 27 and 30
- https://taic.org.nz/sites/default/files/inquiry/documents/07-115%20V%20FINAL.pdf See Page 2
- https://taic.org.nz/sites/default/files/inquiry/documents/07-115%20V%20FINAL.pdf See Page 2
- Bromby 2003, p. 39.
- https://paperspast.natlib.govt.nz/newspapers/NZH19330906.2.132 NZ Herald 6 Sept 1933
- Bromby 2003, p. 38.
- Lyn Humphreys, "Train ban may derail $100 million film", Taranaki Daily News, 23 March 2007
- Author unknown, "Rail Revival Plans", Taranaki Daily News, 11 June 2007.
- Richard Wood, "Fight looms to keep rail line open", Taranaki Daily News, 14 June 2007.
- Toll Rail timetable
- Mathew Dearnaley (9 November 2009). "Line's mothballing sets off alarm bells". New Zealand Herald. Retrieved 10 November 2009.
- Ray Cleaver (15 July 2010). "All aboard the Whanga Express?". Stratford Press. Retrieved 8 September 2010.
- RILKOFF, MATT (22 May 2012). "Kiss of life for old railway". Taranaki Daily News. New Plymouth: Fairfax NZ News. Retrieved 22 May 2012.
- "SOL disappears from the KiwiRail network from tomorrow". The Express. KiwiRail (143): 3. 17 May 2012.
- "The Transport Worker - RMTU - In the midst of a growth wave" (PDF). Rail & Maritime Transport Union. March 2019. Retrieved 25 March 2019.
- The Snail Rail, New Plymouth's first railway
- Coal may save railway line (April 2011)
- Private operator on the line
- Slide show of the line
- News item on the initiative
- Journey to New Zealand's forgotten world (May 2015)
- 1923 photos of road/rail bridge under construction
- 1929 photos of tunnel, pack horses and construction camp
- 1931 photo of No.4 tunnel portal during construction
- The Stratford-Okahukura Line: Fifty Years of Service by R. B. Alexander (First Edition 1961; Second Edition, revised and enlarged 1983; New Zealand Railway and Locomotive Society Inc).
- Taranaki's First Railway by A. B. Scanlan (1977, New Plymouth)
- Down the Line by Karen Goa in Heritage New Zealand Issue 128, Autumn 2013 pp42–47 (about the Twenty Tunnel Tour)
- Bromby, Robin (2003). Rails that built a Nation: An Encyclopaedia of New Zealand Railways. Wellington: Grantham House. ISBN 1-86934-080-9.