Midland line
TwoDX class locomotives inTranz RailBumble-bee livery hauling a 1,800 tonne coal train on the Midland line in 2006.
Overview
Status	Open to passengers and freight
Owner	KiwiRail
Locale	South Island,New Zealand
Termini	Rolleston,Canterbury Greymouth,West Coast
Service
Type	Heavy Rail
System	New Zealand railway network
Operator(s)	KiwiRail The Great Journeys of New Zealand
History
Opened	4 August 1923 (complete line)
Technical
Line length	212 km (132 mi)
Character	Main line
Track gauge	3 ft 6 in (1,067 mm)
Electrification	1500V DC (Arthurs Pass to Otira, 4 August 1923 – 1 November 1997)
Maximum incline	3% (1 in 33) inOtira Tunnel
Route map Legend km h:mm Main North Line toKaikōura andPicton 00.5 0:00 Christchurch 00.0 0:01 start ofMain North Line Main South Line toLyttelton 0:01 Addington Junction Main South Line Middleton Sockburn Hornby Hornby Industrial Line (formerlySouthbridge Branch) Islington Templeton Weedons 31.9 0:19 Rolleston Main South Line toTimaru andDunedin andInvercargill 00.0 0:20 start ofMidland line Sandy Knolls Aylesbury Kirwee 0:38 Darfield Whitecliffs Branch toWhitecliffs Racecourse Hill Waddington Oxford Branch toMain North Line Sheffield Annat 1:00 Springfield Kowai viaduct Little Kowai Bridge Kowai Bush Tunnel 1 Paterson's Creek bridge Tunnels 2 - 4 Tunnels 5 - 7 Staircase Staircase viaduct Tunnels 8 - 10 Broken River viaduct Tunnel 11 (daylighted 2011) Tunnels 12 - 16 Bridge 28 "Slovens Creek" Avoca Craigieburn 1:57 Cass Cass River bridge Waimakariri River bridge Cora Lynn Bealey River bridge Rough Creek bridge 2:27 Arthur's Pass Bealey River bridge (East Portal) Otira Tunnel 8.566 km 5.323 mi Rolleston River bridge (West Portal) Goat Creek bridge 2:48 Otira Kellys Creek Bridge Aickens Ricky Creek Bridge 3:07 Jacksons Taramakau River bridge Inchbonnie Poerua Rotomanu Te Kinga Crooked River bridge Ruru 3:32 Moana Kotuku Arnold River bridge Tunnel 18 (Kaimata) Kaimata 3:48 Kokiri Stillwater–Ngākawau Line toWestport andNgakawau Stillwater Tunnel 19 (daylighted 2010) Brunner Dobson Kaiata Omoto Rapahoe Branch (formerlyRewanui Branch) 212.0 4:30 Greymouth Greymouth Yard Hokitika Branch (formerly toRoss) km h:mm This diagram: view talk edit

Map

TheMidland line is a 212 km section of railway betweenRolleston andGreymouth in theSouth Island ofNew Zealand. The line features five major bridges, five viaducts and 17 tunnels, the longest of which is theOtira tunnel. It is the route of the popularTranzAlpine passenger train.

Railway development in the South Island in the 1870s was concentrated on a main line linking the established centres of Christchurch, Timaru, Dunedin and Invercargill and light, easily constructed branch lines serving the arable plains; (seeVogel Era). These later included a branch to Springfield which was reached by January 1880.

In 1882 the East and West Coast Railway League was formed and in 1884 a Royal Commission, although fully aware of the construction difficulties of the Waimakariri Valley-Arthurs Pass route, as compared with the somewhat easier but longer Hurunui Valley-Harpers Pass route, chose the more direct route.

The construction of the line was rejected in 1883 by a Royal Commission, who argued that despite the significant timber and coal resources of theWest Coast of the South Island, the line would not be economic, in the face of limited resources during the Premiership of SirJulius Vogel, although Parliament did pass theEast and West Coast and Nelson Railway Act to enable private interests to construct a line. The major obstacle to engineers and politicians was theSouthern Alps. In 1886 theNew Zealand Midland Railway Company was formed by Nelson and Canterbury business interests to construct the line, and the line fromWestport toNelson, and capital was raised in London by the firm to meet this end. The Company entered into a contract with the Government the same year.

For various reasons, the company managed to complete only 120 km of the line, and the Government exercised its right to take possession of the line in 1895, although protracted legal battles meant that full control was not achieved until 1900, with the line complete as far asOtira on the western side and Broken River on the eastern (Canterbury) side.

The major obstacle to the route lay immediately ahead: the forcing of theWaimakariri and Broken River gorges, some 8.5 miles (13 km) of the route surveyed by C. Napier Bell in 1883 and described to the Royal Commission by District Engineer W.N. Blair as "very rough, the mountain slope rises from the riverbed while the river runs in a fearful gorge all the way".

The section would include 16 tunnels and four major viaducts not including the Kowai already constructed. The viaducts were built under Treasury contracts by both New Zealand and British bridging firms. The most spectacular of these, the Staircase Viaduct carries the rails 75 metres above the bed of the stream.

It was slow laborious work with men, horses, picks, shovels and very little machinery. It was not until 1906 that trains were running to a temporary terminus at Broken River – in time for the Christchurch Exhibition and at last enabling the journey, by rail and coach, from Greymouth to Christchurch to be completed in one day. Progress slowed after that although the country to be traversed became much easier. Cass was not reached until 1910 and Arthur's Pass township in 1914 – the Westland section meantime having advanced to Otira – to meet the other major obstacle.

Construction ofOtira Tunnel began in 1907, but progress was very slow. By 1912 only 2.9 km of the projected 9 km length of tunnel was complete and in 1913 the initial contractor walked off the job. In the interim the eastern railhead reachedArthur's Pass in 1914. Cobb & Co coaches were used to transport passengers between the two railheads while the tunnel was under construction. Undeterred the government continued with construction, despite spiralling costs and labour shortages due toWorld War I. The tunnel was finally completed in 1923.^[1]

The Great Journeys of New Zealand train, theTranzAlpine, travels this line. The service operates 7 days as Trains 803 and 804 usingDX class locomotives andAK class passenger carriages.

Freight on the line depends largely on coal traffic, with other general freight being restricted to products from theWestland Milk Products factory atHokitika. In 2003,Tranz Rail carried a total of 2.1 million tonnes of coal over the line.

Usually, coal services are headed by two classDX locomotives, and consist of 30 coalhopper wagons, with a total capacity of 1,800tonnes.

On 27 November 2007, it was announced that coking coal from thePike River Coal mine would be transported toLyttelton for export. Pike River Coal had reserved under contract with Toll Rail 1.3 million tonnes of capacity for their coal on the line, which since upgrading has a total capacity of 4 million tonnes.^[2] However coal from the Pike River facility at Rapahoe stopped since thePike River Mine disaster in November 2010.

The other primary source of coal traffic is from theStockton Mine at Ngakawau, north of Westport. Trains to and from Ngakawau use the Midland line as far as the junction with theStillwater - Westport Line.

The line was unique in New Zealand for its captive use of many different types of locomotives. These locomotives include theK^B class locomotives betweenArthur's Pass andSpringfield, once the second most powerful steam locomotives in New Zealand (after the short-livedGarrattG class). The class were made famous by a documentary named "K^B country", a term that has entered intoNew Zealand railfan jargon. The Garratt G class, by then rebuilt as 'Pacific' type locomotives were also used on this route.

To house the larger and more numerous locomotives, Elmer Lane shed opened at Greymouth in 1928. Then the largestroundhouse in the country, its 70 ft (21 m)turntable replaced an earlier 50 ft (15 m) turntable.^[3]

The Otira tunnel was electrified 1923–1997, and two classes of electric locomotives were used – theEnglish Electric EO class and then theNew Zealand EA class locomotive. Some members of theEW class andED class electric locomotives were also used.

Diesel traction was introduced to the line in 1968 with the arrival of theDJ class, which until the transfer ofDC class locomotives in the early 1980s from theNorth Island was the dominant motive power on the line. Increasing volumes of coal traffic led to the introduction of theDX class, a number specially modified for use in theOtira Tunnel.^[4]

The line has 16 tunnels including the 8,554mOtira Tunnel and four major viaducts.^[5]

The heights and lengths of the viaducts are:^[5]

Wikimedia Commons has media related toMidland Line, New Zealand.

• 1969 timetable
• "Steam lives on: Kb Country". National Film Unit newsreel on Youtube. 5 December 2015.Archived from the original on 21 December 2021.
• "Ka (steam engine) on Cass Bank". National Film Unit newsreel on Youtube. 5 December 2015.Archived from the original on 21 December 2021.
• "Ka 942 to Arthurs Pass Winter 2014". video on Youtube. 5 December 2015.Archived from the original on 21 December 2021.
• "A Kb loco-hauled freight train approaching the Alps (undated photo)". NZRLS. 2022.
• Patterson's Creek viaduct (photo)
• Derailment near Cora Lynn, 1923 (photos)
• Derailment near Cora Lynn, 1923 (more photos)
• Ontrack: 90m Tunnel near Kiwi Point, Greymouth daylighted, 2011

• Railway lines in New Zealand
• 3 ft 6 in gauge railways in New Zealand
• Rail transport in the Canterbury Region
• Rail transport in the West Coast Region

• Articles with short description
• Short description matches Wikidata
• Use dmy dates from August 2015
• Use New Zealand English from August 2015
• All Wikipedia articles written in New Zealand English
• Commons category link is on Wikidata
• Pages using the Kartographer extension