Talk:Seikan Tunnel

Did you know?
In case you were wondering, the DYK was "...that the Seikan Tunnel (connecting the islands of Honshu and Hokkaido in Japan) is currently the longest railway tunnel in the world, and will be until the new Gotthard Base Tunnel (Switzerland), with a length of 57 km (36 miles), is opened?--Commander Keane 13:23, 22 May 2006 (UTC)

Stability question
Just wondering how the dynamite effected the stability of the rock - compared with boring? CustardJack 15:24, 6 May 2005 (UTC)
 * It is a good question, and I'll answer it as best as I can with my limited knowledge.


 * By "boring" I'm assuming you mean Tunnel Boring Machine (TBM). As the article suggests TBM was abandoned due to the high variabiliy and fagility of the rock.  (TBM's are best used in rock with uniform properties, rather than the varying strata, soft and fissured rock found in the Seikan.)  Since the rock made a TBM difficult to direct and caused damage to the TBM, a more direct (but slower) approach of blasting and picking was used (Picking was used in the worst rock conditions).  Blasting and picking can be targeted and optimised for each different situation encountered along the route, so a safe level of stability can be achieved.


 * An example of the advantage of blasting as compared to TBM in the Seikan tunnel was the use of different cross sections in different rock stability situations. Because of blasting's targeting ability, in the worst stabilty situations along the tunnel route (mid-way along the Strait) instead of the traditional circular bore made in one pass from a TBM, a circular cross seection was blasted in 4 sub cros ssections.  First two small circular bores, then the rest in two goes (top drift and bottom drift).  Naturally, with steel/concrete reinforcement put in place after each of the four passes, blasting proved a much more stable option than TBM. --Commander Keane 4 July 2005 20:50 (UTC)

Removed link
I removed the link to a Babelfish translation of the Japanese external link. Here are samples of the Babelfish translation:

"This adapter unit did from the tunnel and the bridge and the earth laid etc., as for operation of main island one the Japanese railroad constructive public corporation Morioka branch office, as for the Hokkaido one the Sapporo branch office, as for the blue 函 tunnel blue 函 constructive bureau constructed."

"In the blue 函 tunnel, in order for the seawater not to exert adverse effect on the concrete slab track, the corrosion resistance in sea water moderate heat Portland cement is used, as the crack crack does not occur, the special throb which introduces prestressing is used."

I'm putting the link here so interested parties can find it; it doesn't seem clear enough for a general readership.

Safety
Given the designed in safety factors of the Channel Tunnel, are the Japanese sure that the Seikan Tunnel meets acceptable safety limits ? One would assume so, however it can't be missed that this tunnel is only one tunnel, whereas the Channel Tunnel is 3 tunnels, one a specific safety tunnel. Does anybody know the Japanese view on this ?--jrleighton 12:13, 9 February 2006 (UTC)


 * I'm interested too, I might have a dig around for some info although I'm not sure if this sort is published. Keep in mind that when constructed the Seikan had:
 * A pilot bore (small diameter)
 * A service tunnel (larger diamter, I'm sure of it's current usability)
 * The main bore
 * So it's comparable to the Channel Tunnel.--Commander Keane 12:23, 9 February 2006 (UTC)

Ideas for expansion
--Commander Keane 00:06, 17 May 2006 (UTC)
 * Inundations (safety and pumping stations))
 * Grouting procedures
 * Constructions procedures (steel ribs, cross section selection)
 * Images of the cross sections, top and side views of the entire tunnel
 * Current passenger and freight usage and its market share compared to other modes Softgrow 00:17, 17 May 2006 (UTC)

The fate of Yoshioka-Kaitei
Hmm. JRTR says the station was "demolished", but ja-wiki merely states that it's no longer served by scheduled traffic (定期列車の停車がなくなる). Who's right? Jpatokal 16:27, 18 May 2006 (UTC)


 * I am no tunnel expert but from what I have seen and learnt about tunnel building and mining I think it is more or less obvious what they have done. When working in long tunnels or deep mines usually they have some wider areas and/or side rooms where they can store, park and service equipment and vehicles, have a lunch room and restroom for the workers and so on. Usually those side rooms have their own shafts/elevators to the surface etc. My guess is that both those stations had that purpose during the original building of the tunnel. And that they now removed/demolished the contents of the Yoshioka-Kaitei station to make room to once again use it as such a service side area. --David Göthberg 03:07, 11 June 2007 (UTC)


 * Oh, I just noticed that the Yoshioka-Kaitei Station article says the same. It says: "the station was shut down and to be used as storage space for Hokkaidō Shinkansen building materials." --David Göthberg 03:16, 11 June 2007 (UTC)

Tunnel is on an incline?! What the??
Am I seeing things correctly - in the diagram it shows the tunnel sloping downwards and then upwards - I've never seen a tunnel like this before. How would the passengers keep their drinks/food on the table and prevent them from spilling if this was the case? Seems like it would be an uncomfortable journey... Davez621 (talk) 12:38, 24 June 2008 (UTC)


 * The diagram is just compressed lengthways for clarity. The tunnel is built to shinkansen high-speed line standards, so the gradients aren't even noticeable in practice. --DAJF (talk) 12:45, 24 June 2008 (UTC)

Length
It looks really strange to spell out such common units as km, especially where two English spellings exist (“kilometer“ or ”kilometre”). Even the MOSNUM allows us to use the abbreviation “km” here. I suggest to revert the last change. --Bk1 168 (talk) 05:12, 8 September 2010 (UTC)

Name Seikan not explained
The article fails to explain where the name Seikan comes from. --93.220.55.141 (talk) 13:18, 15 October 2010 (UTC)


 * Added. Jpatokal (talk) 23:21, 15 October 2010 (UTC)

March 2011 great earthquake
Seeing no edits on the article or here since the great earthquake of March 11, I presume "no news is good news" re. the effect on the tunnel? If any reliable information is available, it seems it would be good to discuss it here and possibly include it in the article. Thanks. Wwheaton (talk) 14:37, 13 March 2011 (UTC)

Once the tunnel was completed, all railway transport between Honshu and Hokkaido used the tunnel.
Had there been any such rail-traffic before completion? Wasn't there only sea there? — Preceding unsigned comment added by 5.71.127.36 (talk • contribs) 16:23, 14 August 2014 (UTC)


 * It probably needs to be added to the article to clarify the wording, but before the tunnel opened, trains were loaded on ferries. --DAJF (talk) 23:24, 14 August 2014 (UTC)

External links modified
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 * Added archive http://web.archive.org/web/20090808024548/http://www.popularmechanics.com:80/science/extreme_machines/4217338.html?series=23 to http://www.popularmechanics.com/science/extreme_machines/4217338.html?series=23

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Travel duration Tokyo to Sapporo from March 26, 2016
Now, with the Shinkansen carrying passengers thru Tunnel {Shinkansen terminating at Hakodate} the duration of travel from Tokyo to Sapporo is roughly 7 hours 40 minutes. A reduction of 1½ hours from the 9 hours in the article. The big *if* is when the shinkansen can complete the entire journey to Sapporo, as that stretch is still 3½ hours. When this is completed, it should be 45 minutes from Hakodate to Sapporo; for a total journey time of 4½ hours thereabouts. Alas, these times do not include delay/transfers. as it is still currently 2 different rail companies for Honshu & Hokkaido - so without fluent Japanese it is hard to get a link from the Rail Network(s) websites.

However, this Wiki article may need to be referenced for detail/clarity: 80.5.219.60 (talk) 09:23, 26 May 2016 (UTC)


 * The current (Aug 2016) average journey time for Tokyo to Sapporo by rail throughout (by Shinkansen to Shin-Hakodate-Hokuto, then conventional rail) is 8 hours and 12 minutes. The average journey time for central Tokyo to central Sapporo by rail-air-rail (flying between Tarita and New Chotose airports) is 4 hours and 51 minutes.
 * The fare levels on the two modes are nearly identical: typically ¥25,070 by rail (including compulsory reservation on the Shikansen) and ¥25,190 by rail-air-rail. (Source: http://www.hyperdia.com).
 * What we (or, at least, I) lack at present is a source for the current split between the two modes in terms of passenger numbers. The article claims a 90% share for air travel, but the source given is 15 years old. Would appreciate it if anyone could point me to the 2016 figures before I have a go at updating the article in line with the preceding. -- Picapica (talk) 17:01, 28 August 2016 (UTC)

External links modified
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Longest but not longest, yet longest?
There has to be a sentence with better clarity than: "The Seikan Tunnel is the world's longest tunnel with an undersea segment (the Channel Tunnel, while shorter, has a longer undersea segment)." Arcsoda (talk) 15:06, 22 March 2021 (UTC)


 * Seems quite clear to me --Ita140188 (talk) 14:34, 24 March 2022 (UTC)