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CUT AND FILL?

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CUT AND FILL?
Posted by al-in-chgo on Sunday, April 20, 2008 8:16 PM

I was pondering the rise of RT development in N. America over the past so many years, and I can't think of a line with any significant underground component that has been built or overhauled since the 1970s and the D.C. Metro. 

I myself would not count something like Chicago's Blue Line because practically all the tunneling was completed by the mid-to-late Sixties; and all the airport expansion needed was to duck under a couple of superhighways and get to the terminal. 

But of new dedicated systems like Miami's Metrorail, they are almost always meant to be in the open as much as possible, aren't they?  A friend of mine says that if Manhattan were growing into a high-rise city today, there wouldn't be any IRT because land acquisition would cost too much.  He has a point, but I'm not sure if I can verify that in such a cut-and-dried way.

Comments, observations, thoughts....?

al

 

 

 

al-in-chgo
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Posted by paulsafety on Sunday, April 20, 2008 9:07 PM

The cost of building the infrastructure is extremely high -- existing utilities must be carefully located, marked and moved with regard to service interuptions.  Cut and cover techniques disrupt surface transit, cars, trucks, and access to local businesses.  TBMs and other traditional tunneling methods are also expensive.

If constructing a new line, the cost of signals, track and equipment is significantly compounded by digging and placing it all under the street.  Most new systems have been above ground.  I can't state with authority that the reason was cost of tunneling versus placing tracks in the street or on private right of way, but it makes some sense.

The last underground systems built from scratch include Atlanta, Baltimore, LA (red line) and DC.  Presently, the second ave line is being built in NYC using TBMs, and the ARC plan calls for two new tunnels under the Hudson River to a six track, two level station under 34th Street.  East side access also calls for extensive tunneling.

Not sure that this helps, but that;s my two cents.

 

Paul

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Posted by nanaimo73 on Sunday, April 20, 2008 9:15 PM

The Canada Line is being constructed with both TBM tunneling and cut/cover, between downtown Vancouver and the airport.

http://www.canadaline.ca/

Dale
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Posted by al-in-chgo on Sunday, April 20, 2008 9:44 PM

 

In for a dime, in for a dollar:  what does "TBM" mean? 

 

al-in-chgo
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Posted by MP57313 on Monday, April 21, 2008 4:00 PM

 al-in-chgo wrote:
 what does "TBM" mean? 

Tunnel Boring Machine.

As this is written, the LA MTA is extending its Gold Line from LA Union Station south then east into East L.A.  Part of that line was constructed underground, using TBMs (as did the Red Line cited above).  The Gold Line extension is not yet open; I think there is still a year or so to go.

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Posted by al-in-chgo on Monday, April 21, 2008 5:27 PM
 MP57313 wrote:

 al-in-chgo wrote:
 what does "TBM" mean? 

Tunnel Boring Machine.

As this is written, the LA MTA is extending its Gold Line from LA Union Station south then east into East L.A.  Part of that line was constructed underground, using TBMs (as did the Red Line cited above).  The Gold Line extension is not yet open; I think there is still a year or so to go.

Does the Wilshire Line count as a subway?  IIRC it is heavy rail and is under Wilshire Avenue, at least.  - a.s.

 

al-in-chgo
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Posted by blue streak 1 on Thursday, April 24, 2008 1:52 PM
Miami has an obvious answer = water table and hurricanes
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Posted by MP57313 on Friday, April 25, 2008 12:54 AM

Does the Wilshire Line count as a subway?  IIRC it is heavy rail and is under Wilshire Avenue, at least.  - a.s.

As far as I know, yes.  It is a subway for its entire route, except for the far eastern section, where the yard and shops are out in the open, a little bit south of LA Union Station.

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Posted by gardendance on Saturday, April 26, 2008 9:19 AM

Does anybody know any other examples of complete subway except for yards or 1 station?

Broad Street-Ridge Avenue subways in Philadelphia are underground, except for the last stop, Fern Rock, which is at the yard.

Patrick Boylan

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