Undersea railway tunnel in Japan
The
Seikan Tunnel
(
Japanese
:
?函トンネル
,
Seikan Tonneru
or
?函隧道
,
Seikan Zuid?
) is a 53.85 km (33.46 mi)
dual-gauge
railway tunnel in
Japan
, with a 23.3 km (14.5 mi) portion under the seabed of the
Tsugaru Strait
, which separates
Aomori Prefecture
on the main Japanese island of
Honshu
from the northern island of
Hokkaido
. The track level is about 100 m (330 ft) below the seabed and 240 m (790 ft) below sea level.
[2]
The tunnel is part of the standard-gauge
Hokkaido Shinkansen
and the narrow-gauge
Kaiky? Line
of the
Hokkaido Railway Company
(JR Hokkaido)'s
Tsugaru-Kaiky? Line
. The name
Seikan
comes from combining the
on'yomi
readings of the first characters of
Aomori
(
?森
)
, the nearest major city on the Honshu side of the strait, and
Hakodate
(
函館
)
, the nearest major city on the Hokkaido side.
The Seikan Tunnel is the world's
longest undersea tunnel
by overall length (the
Channel Tunnel
, while shorter, has a longer undersea segment).
[3]
It is also the second-deepest transport tunnel below the sea level after the
Ryfylke Tunnel
, a road tunnel in Norway which opened in 2019, and the second
longest main-line railway tunnel
after the
Gotthard Base Tunnel
in Switzerland, opened in 2016.
[4]
[5]
[6]
Overview
[
edit
]
The tunnel was constructed using conventional construction methods (partly TBM method and new Austrian tunnel method). The construction cost of the tunnel itself was 538.4 billion yen at the planning stage, but it actually cost 745.5 billion yen. The construction cost of the strait line, including the attachment line, was 689 billion yen at the planning stage, but the actual cost is 900 billion yen. The number of casualties in the construction was 34.
Unlike the start of construction during the heyday of the Seikan route, even in eastern Japan, passenger traffic to Hokkaido was already dominated by aircraft, and the construction of the Hokkaido Shinkansen was frozen when it was completed. On the freight side, due to the deterioration of labor-management relations at the JNR at the time, including the frequent occurrence of strikes and legal compliance struggles, freight transportation continued to stagnate as it lost market share to ferries and coastal shipping. In addition, since the maintenance cost is large, such as the need to pump a large amount of spring water even after completion, even a huge investment is regarded as a sunk cost, and it is said that it is more economical to abandon it, and it was ridiculed as "
Showa's Three Idiots Assessment
", "useless long things", and "quagmire tunnel".
However, after its opening, it has played an important role in freight transportation by JR Freight between Hokkaido and Honshu, and has made 21 round trips (regular trains) a day. Including special trains, there are about 50 freight trains up and down. The effect of being able to achieve stable and safe transportation that is not affected by the weather has been significant, and in particular, the transportation volume of agricultural products, which are a key industry in Hokkaido, has increased dramatically.
History
[
edit
]
Connecting the islands
Honshu
and
Hokkaido
by a fixed link had been considered since the
Taish? period
(1912?25), but serious
surveying
commenced only in 1946, induced by the loss of overseas territory at the end of World War II and the need to accommodate returnees. In 1954, five ferries, including the
T?ya Maru
, sank in the Tsugaru Strait during a typhoon, killing 1,430 passengers. The following year,
Japanese National Railways
(JNR) expedited the tunnel feasibility study.
[7]
Also of concern was the increasing traffic between the two islands. A booming economy saw traffic levels on the JNR-operated Seikan Ferry double to 4,040,000 passengers/year from 1955 to 1965, and cargo levels rose 1.7 times to 6,240,000 tonnes/year. Inter-island traffic forecast projections made in 1971 predicted increasing growth that would eventually outstrip the ability of the ferry pier facility, which was constrained by geographical conditions.
[
citation needed
]
In September 1971, the decision was made to commence work on the tunnel. A
Shinkansen
-capable cross section was selected, with plans to extend the Shinkansen network.
[7]
Arduous construction in difficult geological conditions proceeded. Thirty-four workers were killed during construction.
[8]
On 27 January 1983, Japanese Prime Minister
Yasuhiro Nakasone
pressed a switch that set off a blast that completed the
pilot tunnel
. Similarly on 10 March 1985, Minister of Transport
Tokuo Yamashita
symbolically bored through the main tunnel.
[7]
The necessity for the project was questioned at times during construction, as the 1971 traffic predictions were overestimates. Instead of the traffic rate increasing as predicted to a peak in 1985, it peaked earlier in 1978 and then proceeded to decrease. The decrease was attributed to the slowdown in Japan's economy since the first oil crisis in 1973 and to advances made in air transport facilities and longer-range sea transport.
[9]
The tunnel was opened on 13 March 1988, having cost a total of
¥
1.1 trillion (US$7 billion) to construct, almost 12 times the original budget, much of which was due to inflation over the years.
[10]
To commemorate the event, a
commemorative 500 yen coin
depicting the tunnel was issued by the
Japan Mint
in 1988.
[11]
Once the tunnel was completed, all railway transport between Honshu and Hokkaido used it. However, for passenger transport, 90% of people use air travel due to the speed and cost. For example, to travel between
Tokyo
and
Sapporo
by train takes eight hours (Tokyo station and Shin-Sapporo station), with transfer from Shinkansen to narrow-gauge express train at Hakodate. By air, the journey is 1 hour and 45 minutes, or 3 hours and 30 minutes including airport access times. Deregulation and competition in Japanese domestic air travel has brought down prices on the Tokyo-Sapporo route, making rail more expensive in comparison.
[12]
The
Hokutosei
overnight train service began after the completion of the Seikan Tunnel;
[13]
a later and more luxurious
Cassiopeia
overnight train service was often fully booked. Both were withdrawn following the commencement of
Hokkaido Shinkansen
services (in August 2015 and March 2016 respectively), with freight trains being the only regular service utilising the narrow gauge line since that time.
[14]
[15]
JR Hokkaido is exploring the use of "
Train on Train
" technology to remove the threat that the
shock wave
created in front of Shinkansen trains traveling at full speed poses to freight trains operating on Japanese standard
narrow-gauge
track in a tunnel setting. If successful, it will allow the Hokkaido Shinkansen to travel at full speed inside the tunnel in the future.
[16]
As of March 2019, Shinkansen trains operate through the tunnel to
Shin-Hakodate-Hokuto Station
in
Hakodate
, connecting Tokyo and Shin-Hakodate-Hokuto stations in 3 hours and 58 minutes, at a maximum speed of 160 km/h (100 mph) within the tunnel and 260 km/h (160 mph) outside it, and 320 km/h (200 mph) to the south of Morioka.
[17]
It was expected that by 2018 one daily service will be run at 260 km/h (160 mph) through the tunnel. The final stage is proposed to open to
Sapporo Station
in 2031 and is expected to shorten the Tokyo-Sapporo rail journey to five hours. The
Hokkaido Shinkansen
will be operated by
JR Hokkaido
.
Construction timeline
[
edit
]
- 24 April 1946: Geological surveying begins.
[7]
- 26 September 1954: The train ferry
T?ya Maru
sinks in the Tsugaru Strait.
[7]
- 23 March 1964: Japan Railway Construction Public Corporation is established.
[7]
- 28 September 1971: Construction on the main tunnel begins.
[7]
- 27 January 1983: Pilot tunnel breakthrough.
[7]
- 10 March 1985: Main tunnel breakthrough.
[7]
- 13 March 1988: The tunnel opens.
- 26 March 2016: Shinkansen services commence operation through the tunnel, regular narrow gauge passenger services through the tunnel cease.
[18]
Surveying, construction and geology
[
edit
]
Tsugaru Strait traffic data
Year
|
Passengers
(persons/yr)
|
Freight (t/yr)
|
Mode
|
1955
|
2,020,000
|
3,700,000
|
Seikan Ferry
[7]
|
1965
|
4,040,000
|
6,240,000
|
Seikan Ferry
[7]
|
1970
|
9,360,000
|
8,470,000
|
Seikan Ferry
[7]
|
1985
|
9,000,000
[t 1]
|
17,000,000
|
1971 Forecast
[7]
|
1988
|
~3,100,000
|
?
|
Seikan Tunnel
[12]
|
1999
|
~1,700,000
|
?
|
Seikan Tunnel
[12]
|
2001
|
?
|
>5,000,000
|
Seikan Tunnel
[12]
|
2016
|
2,110,000
|
?
|
Seikan Tunnel
(
Hokkaido Shinkansen
)
[19]
|
- ^
This may be a typographical error in the source
|
Surveying started in 1946 and construction began in 1971. By August 1982, less than 700 metres of the tunnel remained to be excavated. First contact between the two sides was in 1983.
[20]
The
Tsugaru Strait
has eastern and western necks, both approximately 20 km (12 mi) across. Initial surveys undertaken in 1946 indicated that the eastern neck was up to 200 metres (656 feet) deep with volcanic geology. The western neck had a maximum depth of 140 metres (459 feet) and geology consisting mostly of sedimentary rocks of the
Neogene
period. The western neck was selected, with its conditions considered favourable for tunnelling.
[21]
The geology of the undersea portion of the tunnel consists of volcanic rock,
pyroclastic rock
, as well as sedimentary rock of the Neogene period.
[22]
The area is folded into a nearly vertical
syncline
, which means that the youngest rock is in the centre of the strait and encountered last. Divided roughly into thirds, the Honsh? side consists of volcanic rocks (notably andesite and basalt); the Hokkaido side consists of sedimentary rocks (notably
Tertiary
period
tuff
and
mudstone
); and the centre portion consists of
Kuromatsunai
strata
(Tertiary period sand-like mudstone).
[23]
Igneous
intrusions
and faults caused crushing of the rock and complicated the tunnelling procedures.
[21]
Initial geological investigation occurred from 1946 to 1963, which involved drilling the sea-bed,
sonic surveys
, submarine boring, observations using a mini-submarine, as well as seismic and magnetic surveys. To establish a greater understanding, a horizontal pilot boring was undertaken along the line of the service and main tunnels.
[21]
Tunnelling occurred simultaneously from the northern end and the southern. The dry land portions were tackled with traditional mountain tunnelling techniques, with a single main tunnel.
[21]
However, for the 23.3-kilometre (14.5 mi) undersea portion, three bores were excavated with increasing diameters respectively: an initial pilot tunnel, a service tunnel, and finally the main tunnel. The service tunnel was periodically connected to the main tunnel with a series of connecting
drifts
, at 600?1,000-metre (1,969?3,281 ft) intervals.
[23]
The pilot tunnel serves as the service tunnel for the central five-kilometre portion.
[21]
Beneath the Tsugaru Strait, the use of a
tunnel boring machine
(TBM) was abandoned after less than two kilometres (1.2 miles) owing to the variable nature of the rock and difficulty in accessing the face for advanced grouting.
[22]
[21]
Blasting with dynamite and mechanical picking were then used to excavate.
Maintenance
[
edit
]
A 2002 report by Michitsugu Ikuma described, for the undersea section, that "the tunnel structure appears to remain in a good condition."
[24]
The amount of inflow has been decreasing with time, although it "increases right after a large earthquake".
[24]
In March 2018 at 30 years of age, maintenance costs amounted to 30 billion Yen or US$286 million since 1999. Plans are to increase speed and provide mobile communication at the full track.
[25]
Structure
[
edit
]
Initially, only
1,067 mm
(
3 ft 6 in
)
narrow-gauge track
was laid through the tunnel, but in 2005 the
Hokkaido Shinkansen
project started construction which included laying
dual gauge
track (providing
standard gauge
track capability) and extending the
Shinkansen
network through the tunnel. Shinkansen services to
Hakodate
commenced in March 2016, and are proposed to be extended to
Sapporo
by 2031. The tunnel has 52 km (32 mi) of
continuous welded rail
.
[26]
Two stations are within the tunnel?
Tappi-Kaitei Station
and
Yoshioka-Kaitei Station
. They serve as emergency escape points. In the event of a fire or other disaster, the stations provide the equivalent safety of a much shorter tunnel. The effectiveness of the escape shafts at the emergency stations is enhanced by having exhaust fans to extract smoke, television cameras to help route passengers to safety, thermal (infrared) fire alarm systems, and water spray nozzles.
[20]
Before the construction of the Hokkaido Shinkansen, both stations contained museums detailing the history and function of the tunnel that could be visited on special sightseeing tours. The museums are now closed and the space provides storage for work on the Hokkaido Shinkansen.
[27]
The two were the first railway stations in the world built under the sea.
[28]
[29]
See also
[
edit
]
References
[
edit
]
- ^
"北海道新幹線、?函トンネル?初の260キロ走行 大型連休の5日間"
. 19 January 2024.
- ^
"Seikan Tunnel Trivia"
.
JR Hokkaido
. Archived from
the original
on 18 October 2016
. Retrieved
17 March
2012
.
- ^
"Turkey Building the World's Deepest Immersed Tube Tunnel"
.
Popular Mechanics
. Archived from
the original
on 8 August 2009
. Retrieved
19 July
2009
.
- ^
"Project data ? raw construction Gotthard Base Tunnel"
(PDF)
. Lucerne, Switzerland: AlpTransit Gotthard AG
. Retrieved
12 May
2016
.
- ^
"Wer hat die grosste Rohre?"
[Who has the longest tube?].
Tages-Anzeiger
(graphical animation) (in German). Zurich, Switzerland. 14 April 2016
. Retrieved
11 May
2016
.
- ^
"Switzerland Is Opening the World's Longest-Ever Rail Tunnel"
.
Bloomberg.com
. 13 May 2016
. Retrieved
13 May
2016
.
- ^
a
b
c
d
e
f
g
h
i
j
k
l
m
Matsuo, S. (1986). "An overview of the Seikan Tunnel Project Under the Ocean".
Tunnelling and Underground Space Technology
.
1
(3?4): 323?331.
doi
:
10.1016/0886-7798(86)90015-5
.
- ^
"Japan Opens Undersea Rail Line"
.
St. Louis Post Dispatch
. Associated Press. 14 March 1988. p. 6B – via
Newspapers.com
.
- ^
Galloway, Peter (25 February 1981). "Japan's super tunnel a political nightmare".
Special to The Globe and Mail
. p. 15.
- ^
Langmead, Donald; Garnaut, Christine (2001).
Encyclopedia of Architectural and Engineering Feats
. ABC-CLIO. p.
301
.
ISBN
9781576071120
. Retrieved
11 March
2018
.
- ^
"?函トンネル開通記念500円白銅貨幣"
[Seikan Tunnel opening commemoration 500 Yen White Copper Coin].
Japan Mint
(in Japanese)
. Retrieved
29 April
2020
.
- ^
a
b
c
d
Takashima, S. (2001).
"Railway Operators in Japan 2: Hokkaido (pdf)"
(PDF)
.
Japan Railway and Transport Review
.
28
: 58?67. Archived from
the original
(PDF)
on 8 January 2006
. Retrieved
24 May
2006
.
- ^
"北斗星"
[Hokutosei] (in Japanese). JR East. Archived from
the original
on 21 December 2014.
- ^
?台特急〈北斗星〉ラストラン
[Last run of
Hokutosei
sleeping car limited express].
RM News
(in Japanese). Japan: Neko Publishing Co. Ltd. 24 August 2015
. Retrieved
2 September
2015
.
- ^
?台特急“カシオペア”運?終了
["Cassiopeia" sleeper services end].
Japan Railfan Magazine Online
(in Japanese). Japan: Koyusha Co., Ltd. 21 March 2016
. Retrieved
22 March
2016
.
- ^
?自の?究開? 人と物流 高速化に活路
[Own R&D leading to increased speed].
Hokkaido Shimbun
(in Japanese). Japan: The Hokkaido Shimbun Press. 20 December 2008
. Retrieved
30 September
2009
.
- ^
"
東京―新函館4時間10分 北海道新幹線、16年春開業
"
.
Nihon Keizai Shimbun
(in Japanese). 16 April 2014
. Retrieved
16 April
2014
.
- ^
"Passengers on Aomori to Hokkaido bullet train enjoy smooth, speedy ride"
.
Mainichi Daily News
. 26 March 2016
. Retrieved
11 March
2018
.
- ^
"?土交通省?道輸送統計年報(平成19年度)"
.
Ministry of Land, Infrastructure, and Transportation
(in Japanese). Archived from
the original
on 14 May 2011
. Retrieved
12 March
2018
.
- ^
a
b
Morse, D. (May 1988). "Japan Tunnels Under the Ocean".
Civil Engineering
.
58
(5): 50?53.
- ^
a
b
c
d
e
f
Tsuji, H., Sawada, T. and Takizawa, M. (1996). "Extraordinary inundation accidents in the Seikan undersea tunnel".
Proceedings of the Institution of Civil Engineers, Geotechnical Engineering
.
119
(1): 1?14.
doi
:
10.1680/igeng.1996.28131
.
{{
cite journal
}}
: CS1 maint: multiple names: authors list (
link
)
- ^
a
b
Paulson, B. (1981). "Seikan Undersea Tunnel".
Journal of the Construction Division
.
107
(3): 509?525.
doi
:
10.1061/JCCEAZ.0000983
.
- ^
a
b
Kitamura, A. & Takeuchi, Y. (1983). "Seikan Tunnel".
Journal of Construction Engineering and Management
.
109
(1): 25?38.
doi
:
10.1061/(ASCE)0733-9364(1983)109:1(25)
.
- ^
a
b
Ikuma, M. (2005). "Maintenance of the undersea section of the Seikan Tunnel".
Tunnelling and Underground Space Technology
.
20
(2): 143?149.
Bibcode
:
2005TUSTI..20..143I
.
doi
:
10.1016/j.tust.2003.10.001
.
- ^
Abe, Hiroaki c.s. (27 March 2018).
"At 30, undersea tunnel requires maintenance, need for speed"
. The Asahi Shimbun
. Retrieved
29 September
2018
.
- ^
"Seikan Tunnel Museum"
.
記念館案? ?函トンネル記念館 公式ホ?ムペ?ジ
(in Japanese). Archived from
the original
on 1 May 2006
. Retrieved
8 May
2006
.
- ^
"March 2006"
.
jrtr.net
. Retrieved
24 May
2006
.
- ^
Ishino, Tetsu; et al., eds. (1998).
停車場?遷大事典 ???JR編
[
Station Transition Directory ? JNR/JR
] (in Japanese). Vol. II. Tokyo: JTB Corporation. p. 830.
ISBN
4-533-02980-9
.
- ^
"World's first undersea station ends operation"
. NHK. Archived from
the original
on 11 November 2013.
External links
[
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]
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