Seibu Shinjuku Line grade crossing scenes

[bikkuri bahn]

Railsquid mentioned in the Todoroki thread about the Seibu Shinjuku Line partial undergrounding. It will result in the elimination of numerous grade crossings in this portion of Nakano Ward, which typically remain open for periods of only 20 to 30 seconds during rush hours, causing major motor traffic congestion. Completion scheduled to be 2020.

 

This is one which will be eliminated, located between Araiyakushi and Numabukuro- officially called the Araiyakushi #2 Crossing, which is where the Nakano Road crosses the Shinjuku Line. Video taken earlier this month.

 

*get your pics while you can...

[railsquid]

It's Araiyakushi-mae btw :D Which is one of the more interesting, or at least less-uninteresting stations on the line - you can see where it once had a third track, and it's at the top of a gentle curved incline which gives good views of the trains.

 

The road shown in the video is probably one of the last remaining major-ish roads in the 23-ku still bisected by a level crossing, and probably the main motivation for the undergrounding.

 

There were apparently plans during the bubble era to quadruple the line by building a two-track tunnel under much of its length and leaving the above-ground portion for local trains only.

[kvp]

Nice location and i especially like the classic stations in the area. I wonder how the bridges will be replaced? Do they plan to go under the channels?

[railsquid]

Not sure what you mean there - they're building a tunnel which will pass under everything.

[kvp]

I thought they are just using the cut and cover method, that puts the line under the surface with only the tunnel ceiling between them. That would put the line roughly at the water level of the channels. Tunneling is more expensive and can't be done with a few excavators and usually it's slower. The middle ground would be deep cut and cover, putting the line at -2 or -3 stories, just below the canals and allows basements for any buildings that might get built above the route. Is there a link to more information about this project?

[bikkuri bahn]

 Is there a link to more information about this project?

 

Try this, it's from Seibu's website:

http://www.seibu-group.co.jp/railways/smile/nakai_nogata/

*click on the 工事の順序 section (the one with the hazard cone symbol), to see animations of construction of each section (combination of shield tunneling and cut and cover, I reckon).

[railsquid]

I thought they are just using the cut and cover method, that puts the line under the surface with only the tunnel ceiling between them. That would put the line roughly at the water level of the channels. Tunneling is more expensive and can't be done with a few excavators and usually it's slower. The middle ground would be deep cut and cover, putting the line at -2 or -3 stories, just below the canals and allows basements for any buildings that might get built above the route.

 

Given the undulating nature of Tokyo's geography west of the Tokaido line, pure cut and cover is pretty much out of the question - most of these projects (e.g. the Odakyu line around Shimokitazawa or Chofu Station on the Keio) are, like bikkuri bahn's link shows, a mix of deep-level cut-and-cover (usually around the stations and the tunnel portals) and deep-level shield tunnels. Which Tokyo has no shortage of, be it railways, rainwater drainage:

or expressways.

 

I always find it fascinating how they manage to excavate the tunnel entrances and stations without interrupting services.

Edited April 28, 2016 by railsquid

[bikkuri bahn]

The Seibu website is riddled with Flash, so an alternative is this:

http://www.city.tokyo-nakano.lg.jp/dept/164000/d004388_d/fil/renritusoan.pdf

[railsquid]

This article (from the section "中野区の中井駅─野方駅間は地下化") has pictures of the level crossings which will be made redundant. The first part of the article is about Higashi-Murayama station, which will be elevated.

[bill937ca]

We are used to streets running away from railway tracks on the diagonal, but how about a twin diagonal  Y-shaped crossing?  Seibu Ikebukuro line #5 crossing.

 

 

Edited April 29, 2016 by bill937ca

[railsquid]

Hah, I used to live near that one. Still there and unlikely to ever be removed; in common with some other lines with thorugh-running, the grade-separation only goes about as far as the connection with the Metro/Toei and the remaining stretch to the traditional terminus stays as it was.

Edited April 28, 2016 by railsquid

[kvp]

 

Given the undulating nature of Tokyo's geography west of the Tokaido line, pure cut and cover is pretty much out of the question

As the old lines followed the surface, it would be possible to follow the surface with the new tunnels too (except where there are canals), but i understand that newer, higher speed lines need more level routes. Also it seems like shield tunneling is more economical after a certain depth.

 

I've seen combined surface/underground/elevated grade separation projects and after understanding how and why the Ginza line ended up on the 3rd floor of Shibuya station these seem logical.

[railsquid]

I've seen combined surface/underground/elevated grade separation projects and after understanding how and why the Ginza line ended up on the 3rd floor of Shibuya station these seem logical.

 

And ironically the river which flows through the valley which the Ginza line straddles (the depot on the other side touches ground again on Dōgenzaka)

 is now channeled through the station complex.

[bill937ca]

Hah, I used to live near that one. Still there and unlikely to ever be removed; in common with some other lines with thorugh-running, the grade-separation only goes about as far as the connection with the Metro/Toei and the remaining stretch to the traditional terminus stays as it was.

 

Interesting to know.