![Hexton Tunnel System Map](https://upload.wikimedia.org/wikipedia/commons/7/74/Hexton_Tunnel_System_Map.svg)
The four Hex River Tunnels consist of a twin tunnel of and three single tunnels of , and , on the Hexton railway route between De Doorns and Kleinstraat through the
Hex River Mountains
The Hex River Mountains ( af, Hexrivierberge) make up the second highest mountain range in the Western Cape province of South Africa and are located 120 kilometres (75 miles) north-east of Cape Town. They form part of a large anticline in the Ca ...
of the
Western Cape
The Western Cape is a province of South Africa, situated on the south-western coast of the country. It is the fourth largest of the nine provinces with an area of , and the third most populous, with an estimated 7 million inhabitants in 2020 ...
Province, South Africa. The line, which connects
De Doorns
De Doorns is situated in the Breede Valley Local Municipality, Cape Winelands District Municipality in the Western Cape province of South Africa.
Location
It lies in the Hex River Valley on the N1 National Route, 32 km north-east of Worcest ...
in the Hex River valley with
Touws River in the
Great Karoo
The Karoo ( ; from the Afrikaans borrowing of the South Khoekhoe !Orakobab or Khoemana word ''ǃ’Aukarob'' "Hardveld") is a semi- desert natural region of South Africa. No exact definition of what constitutes the Karoo is available, so its ex ...
, is part of the main rail route between
Cape Town
Cape Town ( af, Kaapstad; , xh, iKapa) is one of South Africa's three capital cities, serving as the seat of the Parliament of South Africa. It is the legislative capital of the country, the oldest city in the country, and the second largest ...
and
Johannesburg
Johannesburg ( , , ; Zulu and xh, eGoli ), colloquially known as Jozi, Joburg, or "The City of Gold", is the largest city in South Africa, classified as a megacity, and is one of the 100 largest urban areas in the world. According to Demo ...
. Of the of track, are underground. Construction of the line eliminated the bottleneck of the Hex River rail pass.
[South African Construction World, July 1990, pp. 60–61]
The Hex River rail pass
![John Molteno - Cape Prime Minister](https://upload.wikimedia.org/wikipedia/commons/f/fa/John_Molteno_-_Cape_Prime_Minister.jpg)
The enormous
Cape Fold Belt
The Cape Fold Belt is a fold and thrust belt of late Paleozoic age, which affected the sequence of sedimentary rock layers of the Cape Supergroup in the southwestern corner of South Africa. It was originally continuous with the Ventana Mount ...
effectively separated Cape Town on the coast from the hinterland of Southern Africa, and had obstructed previous attempts to expand the Cape Colony's railway infrastructure inland. In 1872 the
Cape Government, under Prime Minister
John Molteno
Sir John Charles Molteno (5 June 1814 – 1 September 1886) was a soldier, businessman, champion of responsible government and the first Prime Minister of the Cape Colony.
Early life
Born in London into a large Anglo-Italian family, Molten ...
, ordered that a railway line must be constructed across this barrier in the vicinity of the
Hex River Mountains
The Hex River Mountains ( af, Hexrivierberge) make up the second highest mountain range in the Western Cape province of South Africa and are located 120 kilometres (75 miles) north-east of Cape Town. They form part of a large anticline in the Ca ...
. The
Cape Government Railways
The Cape Government Railways (CGR) was the government-owned railway operator in the Cape Colony from 1874 until the creation of the South African Railways (SAR) in 1910.
History Private railways
The first railways at the Cape were privately own ...
(CGR) was formed and railway engineer William George Brounger was appointed to oversee the task.
Route
The Hex River Mountain was a major obstacle to be overcome during the construction of the railway between
Cape Town
Cape Town ( af, Kaapstad; , xh, iKapa) is one of South Africa's three capital cities, serving as the seat of the Parliament of South Africa. It is the legislative capital of the country, the oldest city in the country, and the second largest ...
and the diamond fields at
Kimberley in the Northern Cape. In 1874 surveyor Wells Hood, under the instruction of Brounger, found a potential route up the climb from De Doorns in the Hex River valley to the top of the Karoo plateau east of the Valley, that would require gradients of no more than 1 in 40
uncompensated, very steep by railway standards, and tight curves with a minimum radius of . He also proposed that a short tunnel would be required.
By 1876, the Molteno Government had selected Thomas Brounger's proposed route through the Hex River valley, with the line to follow the route from
Worcester
Worcester may refer to:
Places United Kingdom
* Worcester, England, a city and the county town of Worcestershire in England
** Worcester (UK Parliament constituency), an area represented by a Member of Parliament
* Worcester Park, London, Englan ...
through
De Doorns
De Doorns is situated in the Breede Valley Local Municipality, Cape Winelands District Municipality in the Western Cape province of South Africa.
Location
It lies in the Hex River Valley on the N1 National Route, 32 km north-east of Worcest ...
, then along Hood's proposed pass across the mountain via Osplaas to the summit at Matroosberg, and then via Kleinstraat to
Touws River.
Cape Gauge
![Cape Town dual gauge ca 1880](https://upload.wikimedia.org/wikipedia/commons/8/8e/Cape_Town_dual_gauge_ca_1880.jpg)
The original line between
Cape Town
Cape Town ( af, Kaapstad; , xh, iKapa) is one of South Africa's three capital cities, serving as the seat of the Parliament of South Africa. It is the legislative capital of the country, the oldest city in the country, and the second largest ...
and
Wellington
Wellington ( mi, Te Whanganui-a-Tara or ) is the capital city of New Zealand. It is located at the south-western tip of the North Island, between Cook Strait and the Remutaka Range. Wellington is the second-largest city in New Zealand by me ...
was laid to standard gauge, but this gauge could not be accommodated economically on the tight curves required by the proposed Hex River rail pass. This led to a decision by the CGR to use a narrower gauge of across the pass. After initially making use of dual gauge, it was decided in 1873 to convert all existing trackage of the CGR to this narrower gauge that was eventually to become known throughout Africa as
Cape gauge
A cape is a clothing accessory or a sleeveless outer garment which drapes the wearer's back, arms, and chest, and connects at the neck.
History
Capes were common in medieval Europe, especially when combined with a hood in the chaperon. Th ...
. Credit for the fact that most of the present day railway lines in Africa are Cape gauge can therefore be directly attributed to the Hex River rail pass.
First Tunnel
The original tunnel, Southern Africa's first railway tunnel, is situated at from De Doorns on the original line to Matroosberg. The tunnel is straight and the portals are of dressed stone masonry, but the inside is unlined. On the route ascending the mountain, Osplaas provided the only level stretch that was long enough for a conventional passing loop.
Progress of the building of the line: Reached Worcester, 16 June 1876, and by the end of 1977 had reached Montagu Road, now known as Touws River – thus past the tunnel.
Second Tunnel
![Hex River railpass tunnels east](https://upload.wikimedia.org/wikipedia/commons/e/ed/Hex_River_railpass_tunnels_east.JPG)
This first tunnel served the railways for 53 years, until the track was re-laid in 1929 to diminish a curve to accommodate larger locomotives. In the process a new concrete lined curved tunnel was sunk alongside the original. Since another crossing place had also become necessary, a siding named Tunnel was fashioned just east of the tunnel by laying two level dead-end spur tracks that branched directly off on opposite sides of the main line. This allowed trains to wait in one or the other of these sidings to allow an opposing train to pass. This latter tunnel remained in use for sixty years, until the line across the pass was closed to rail traffic in 1989.
[Reader's Digest Atlas of Southern Africa, The Reader's Digest Association South Africa (Pty.) Limited, 1984, (Editor Christopher Walton), p76, ]
Despite its quick and relatively cheap construction, the Hex River rail pass served the
South African Railways
Transnet Freight Rail is a South African rail transport company, formerly known as Spoornet. It was part of the South African Railways and Harbours Administration, a state-controlled organisation that employed hundreds of thousands of people ...
(SAR) for more than a century. It was the starting point of the country's first railway line to the
Witwatersrand
The Witwatersrand () (locally the Rand or, less commonly, the Reef) is a , north-facing scarp in South Africa. It consists of a hard, erosion-resistant quartzite metamorphic rock, over which several north-flowing rivers form waterfalls, which ...
and opened the way for
Cecil Rhodes
Cecil John Rhodes (5 July 1853 – 26 March 1902) was a British mining magnate and politician in southern Africa who served as Prime Minister of the Cape Colony from 1890 to 1896.
An ardent believer in British imperialism, Rhodes and his Br ...
' colonisation thrust into central Southern Africa.
[Hexpas Ecotrek History](_blank)
Current route
The railway line between Cape Town and Beaufort West has a ruling grade of 1 in 66 and a minimum curvature of , except for the pass where the steep gradient and sharp curves restricted train lengths and required additional locomotive power to bank trains on the ascent. In 1943 the gradients between De Doorns and Matroosberg stations were eased to 1 in 40 compensated, while the curves were eased to a minimum radius of , but despite this the Hex River rail pass still formed a bottleneck that would require more drastic measures to be eliminated.
This eventually led to the decision to construct a tunnel system to eliminate the Hex River rail pass altogether. In 1945 Mr W.H. Evans, later to become Chief Civil Engineer of the SAR, proposed a new route for the section between De Doorns and Matroosberg that would result in a gradient of 1 in 66 compensated and a minimum curve radius of . The scheme would require four tunnels, two with a length of each and two more with lengths of and respectively. The benefits to the SAR would be significant. Operating costs would be decreased as a result of the elimination of sharp curves and steep gradients. The length of the section would be reduced by and it would also eliminate altogether 5,280 degrees of curvature and of false rise in level. Train running times could be reduced by 23 minutes in the ascending direction and 36 minutes in the descending direction.
Approval
![Tunnel Hexrivier A 07](https://upload.wikimedia.org/wikipedia/commons/f/f1/Tunnel_Hexrivier_A_07.JPG)
The scheme was approved in 1946 and it was decided that full-face working would be employed in the long tunnel. With this method and working two faces simultaneously, it was expected that complete with lining could be achieved annually, with the whole tunnel completed in four years.
Tunnelling on the subsidiary tunnels and external earthworks commenced immediately, but start of work on the long tunnel was delayed due to special equipment that had to be designed and ordered in 1946. While awaiting the special equipment, the western (Cape Town side) and eastern (Johannesburg side) portals were established by heading and benching, and short sections of tunnel were driven at both ends by 1948. The original eastern portal (coordinates ) was dug immediately adjacent to the N1 national road some west of Touws River and took the form of a cutting into a gradient to sufficient depth to commence tunnelling.
First postponement
In April 1950, however, work on the whole Hexton scheme was deferred for reasons of economy. Instead, the existing line through the pass was electrified by 1954 and operated with the
Class 4E electric locomotives that had been ordered for use through the tunnels. At the time the project was halted, altogether of tunnel had been excavated and of concrete lining had been placed in the shorter tunnels.
Second and third postponements
![Tunnel Hexrivier 1 West](https://upload.wikimedia.org/wikipedia/commons/6/63/Tunnel_Hexrivier_1_West.JPG)
The tunnel scheme was briefly resuscitated in 1965 but was deferred once again in 1966. Work was eventually resumed in 1974 and included the remodelling of the lower section of the deviation between De Doorns and Osplaas stations as well as the construction of tunnel no. 1, the twin tunnels. This was completed in 1976, at which point financial constraints resulted in yet another postponement. Authority to proceed was only given once again in late 1979.
The twin tunnels bored through a hill that was skirted around the western and northern sides by the original alignment to Osplaas. When completed, the south-eastern of the twin tunnels became part of the new alignment of the De Doorns-Osplaas section. The north-western of the twin tunnels was initially used for construction trains working on the rest of the tunnel system and became part of the new route when the tunnel system opened. The south-eastern of the twin tunnels eventually fell into disuse along with the old Hex River Railpass.
Hexton completion
In most respects the scheme as eventually completed was the same as that envisaged in 1945. Before proceeding in 1979, however, a sophisticated evaluation of the capacity of the whole Hexton scheme had been carried out using train diagrams and computer-devised train running times. The conclusion was that, with only two passing loops between De Doorns and Kleinstraat compared to the three at Osplaas, Tunnel and Matroosberg on the existing line, the capacity would be 31 trains, but with an additional passing loop it would increase to 42 trains. It was therefore decided to place a third passing loop, called Hexton, inside the long tunnel in addition to the two loops between tunnels no. 1 and 2 at Almeria and between tunnels no. 3 and 4 at Salbar respectively.
[South African Construction World, May 1990, p. 55 (Diagram)]
Construction
![Tunnel Hexrivier 4 Siding](https://upload.wikimedia.org/wikipedia/commons/2/29/Tunnel_Hexrivier_4_Siding.JPG)
When tenders were invited, two routes had been selected for tunnel no. 4, the longest tunnel. One would be straight and more or less on the original location, but with the eastern portal relocated further away from the N1 national road. The other would be curved to pass through shale material, that would make the use of a tunnel boring machine an economical proposition. Tenderers were invited to quote for circular or horseshoe profiles and concrete or shotcrete linings for each of the two profiles and for each of the proposed routes. After the engineering, geological and economic factors had been analysed, the straight route with a horseshoe profile and concrete lining was finally selected.
The tunnel was constructed by Compagnie Interafricaine De Travaux (Comiat), a division of Spie-Batignolles in Paris, France.
The contract for tunnel no. 4 was awarded on 13 August 1980 at a tender price of R26,770,082 and with the completion date four years later on 12 August 1984. The contractual completion date was later extended to 25 February 1986. Construction commenced in September 1980, with tunnel excavation commencing in January 1981. As a result of unforeseen adverse sub-surface conditions
that were encountered during the execution of the contract, however, the tunnel was only completed in November 1988.
[South African Construction World, October 1990, p. 59]
Tunnels no. 2 and 3 are similar in construction to the long tunnel, but were completed under a separate contract at a cost of R9 million. Both of them had been partly excavated when work was suspended in 1949, the tunnel no. 2 to a distance of of which most was concrete lined, and the tunnel no. 3 to a distance of , but only lined in areas of poor ground. The contract called for both to be widened to new design standards to allow for overhead electrification and broader loading gauge clearances.
[The Civil Engineering Contractor, February 1986, p. 35]
Completion
![Tunnel Hexrivier 4 East](https://upload.wikimedia.org/wikipedia/commons/5/53/Tunnel_Hexrivier_4_East.JPG)
The western portal (coordinates ) of tunnel no. 4, as established in 1948, enters directly into the mountain face, which is nearly vertical at that point. The eastern portal (coordinates ) was relocated a short distance to the southeast of the original 1948 portal and is in a long and deep cutting. The tunnel is long and has a maximum cover of . The gradient is mainly 1 in 66, except at the passing loop where it decreases to 1 in 200. Five ventilation shafts of diameter and with a combined length of were sunk. The cross-sectional area of the horseshoe profile single line tunnel is , but this increases to at the passing loop. Tunnel no. 4 also contains relay rooms for signalling equipment.
The tunnel system became operational in April 1989, more than forty years after the first portals were sunk, and was officially opened on 27 November 1989. The completed four-tunnel system now boasts the longest railway tunnel system in Africa.
[South African Panorama, October 1989, p. 25]
Tunnel 4 was the longest railway tunnel in Africa until 2009. The present longest single railway tunnel in Africa is long, on the
Gautrain
Gautrain is an higher-speed express commuter rail system in Gauteng, South Africa, which links Johannesburg, Pretoria, Kempton Park and O.R. Tambo International Airport. It takes 15 minutes to travel from Sandton to O.R. Tambo International ...
line between
Johannesburg Park Station
Johannesburg Park Station is the central railway station in the city of Johannesburg, South Africa, and the largest railway station in Africa. It is located between the Central Business District and Braamfontein, in the block bordered by Rissik, ...
and
Marlboro
Marlboro (, ) is an American brand of cigarettes, currently owned and manufactured by Philip Morris USA (a branch of Altria) within the United States and by Philip Morris International (now separate from Altria) outside the US. The largest Marl ...
Portal, which was broken through in September 2009.
Ecotourism
Upon the opening of the new route, the line was effectively doubled since the original line across the pass was retained. As a result of already diminishing traffic volumes due to competition from road transport, however, the old Hex River rail pass line was closed to rail traffic and the electrification infrastructure was removed when the Hexton line was opened. A large part of the track between Matroosberg and Osplaas stations was left in place, however, and is now being utilised as a popular tourist destination known as the Hexpas Ecotrek.
[Hexpas Ecotrek – Hexpas Express](_blank)
References
External links
*
{{Locomotives of South Africa
Railway tunnels in South Africa
Tunnels in South Africa
Tunnels completed in 1989
1989 in South Africa