Vision: CBD Underground Rail Loop

[[Shuz]]

I presume you mean Steven Marshall?

It is Liberal Policy to do so come the 2018 election.

[claybro]

I presume you mean Steven Marshall?

It is Liberal Policy to do so come the 2018 election.

Sorry I'm lost. Easy done I know. Is this sarcasm Shuz? The words "Liberal policy" and "Rail" do not compute for me.

[[Shuz]]

You clearly haven't seen or heard of the massive rail infrastructure the WA, VIC and NSW Liberal parties have been investing in recently. Things are a changing.

[claybro]

You clearly haven't seen or heard of the massive rail infrastructure the WA, VIC and NSW Liberal parties have been investing in recently. Things are a changing.

In those states maybe. But given the Liberals here are in a lather about current policy of restricting car access into the CBD and promising to remove the car park levy if gaining office, I would doubt a CBD Rail loop is anywhere on SA Libs radar.In fact, I am sure the SA Libs think anything on rails is the devils work. Do they even have a PT policy?

[monotonehell]

...In fact, I am sure the SA Libs think anything on rails is the devils work. Do they even have a PT policy?

No, but they have a policy to establish a body to talk about having a policy.
http://www.saliberal.org.au/Portals/0/I ... 202036.pdf

[1NEEDS2POST]

For many underground railways built today, the majority of the construction cost is in the stations. This is because stations must be constructed using conventional techniques, whereas the tunnels are often constructed using TBMs.

A recent development is large diameter TBMs. Barcelona's line 9 is under construction with an 11.95 m diameter TBM. Not only can both tracks can fit in the one tunnel, but also the stations themselves can be built inside the TBM's tunnel!

I think this should be explored for an Adelaide CBD tunnel. Excavating the stations under the CBD with conventional techniques looks more expensive than just one large TBM.

Thinking for the far future, once the TBM is finished with the CBD tunnel, it could be used to bore a Mt Lofty Base Tunnel. The TBM's tunnel will be large enough to fit double stacked trains through.

http://www.cat-bus.com/2017/10/barcelon ... pink-line/


http://www.cat-bus.com/2017/10/barcelon ... pink-line/

[PeFe]

Really interesting concept.....however there is one thing that I think is a total disaster, and that is the use of lifts/elevators......very, very, slow at moving passengers up to street level compared to escalators.... also a lot more dangerous if there is a fire.

Modern metro building techniques favour escalators, not lifts.

[Nathan]

Really interesting concept.....however there is one thing that I think is a total disaster, and that is the use of lifts/elevators......very, very, slow at moving passengers up to street level compared to escalators.... also a lot more dangerous if there is a fire.

Modern metro building techniques favour escalators, not lifts.

They should have both. Lifts for those with mobility issues, prams, or luggage; escalators for everyone else.

[PeFe]

Really interesting concept.....however there is one thing that I think is a total disaster, and that is the use of lifts/elevators......very, very, slow at moving passengers up to street level compared to escalators.... also a lot more dangerous if there is a fire.

Modern metro building techniques favour escalators, not lifts.

They should have both. Lifts for those with mobility issues, prams, or luggage; escalators for everyone else.

Yes you're right. Just to clarify I did not mean no lifts....(Nothing for the disabled or infirmed!) I meant as the main transportation mode between the surface and the underground station.

[SBD]

Really interesting concept.....however there is one thing that I think is a total disaster, and that is the use of lifts/elevators......very, very, slow at moving passengers up to street level compared to escalators.... also a lot more dangerous if there is a fire.

Modern metro building techniques favour escalators, not lifts.

They should have both. Lifts for those with mobility issues, prams, or luggage; escalators for everyone else.

Yes you're right. Just to clarify I did not mean no lifts....(Nothing for the disabled or infirmed!) I meant as the main transportation mode between the surface and the underground station.

I think when I visited London some time ago, some of the deep stations had large lifts for normal use. There were stairs, but signed as being for emergency use only, not even permitted for fit people.

It;s interesting that the Barcelona boring machine can have different cutter heads for different geology, but not so inspiring that they started building the new line in 2002 and it is not finished yet.

[Goodsy]

Using that TBM and just having to excavate a cavity for escalators would still be a huge time saver. The only problem would be how to actually get the escalators installed, they're usually craned in from above and installed in 1 piece

[SBD]

Using that TBM and just having to excavate a cavity for escalators would still be a huge time saver. The only problem would be how to actually get the escalators installed, they're usually craned in from above and installed in 1 piece

I saw a documentary about the new cross-city line in London. The escalator had to be installed in 13 pieces that were each small enough to fit through the ticket hall and not damage the roof as they were tipped to slide down the guides.

How deep would a tunnel have to be to avoid all footings and piling under the buildings in Adelaide?

How deep is the water table under the city? What happens if a tunnel is dug below it? Can it just be made watertight, or would the tunnel ultimately "float" out of alignment? The same kind of question would arise for a bored tunnel under the North South Corridor, but roads probably handle not-quite-smooth better than trains do if it floats slightly.

[1NEEDS2POST]

There are TBMs that can dig diagonally down for escalator shafts. Here is an article on one used for the St Petersburg Metro: https://www.tunneltalk.com/TunnelTech-A ... alator.php

[Aidan]

It's station capacity considerations, not construction techniques, which favour escalators rather than lifts. You need a lot of lifts just to match the capacity of one escalator pair.

Tunnelling beneath the water table is not difficult. Though there will be slight ground movements, it won't float out of alignment.

Regarding the footings, it's a mixture — some buildings have shallow (strip or slab) footings, while others have piles. Of those with piles, some don't even reach the limestone layer, some are firmly fixed in it, and others go right through it!

Where roads can be followed, it's probably cheaper not to use a TBM.

[Nort]

In another thread someone mentioned that the Rundle/Pulteney U-Park could be getting close to its end of life in a decade or so. Seems like a perfect spot for an underground station and if they building has to be knocked down anyway would make the excavation a lot easier!