Vision: CBD Underground Rail Loop

[ml69]

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

Why couldn’t they build escalators within that 25m diameter shaft? Yes it will have to zig zag multiple times down to the platform level (much like escalators in a department store) but surely there would be room for it and much better than elevators only.

Also more simple than excavating a separate shaft for an escalator.

[ml69]

I like the idea of a really big 2-level rail tunnel with station incorporated into the tunnel itself.

It mitigates a big concern of mine which was whether we could afford a rail tunnel with multiple CBD stations due to the enormous cost of constructing the underground stations. With this arrangement, station construction is quite straight-forward job.

I was thinking ideal locations for the station entrances (the 25m wide shaft) could be:

- Adelaide (Underground) station: the plaza in front of the Intercontinental (maybe some underground parking might have to be demolished). This could then link to the existing station.

- Hindmarsh Square station: on the southwestern portion of Hindmarsh Square, servicing the eastern part of the CBD. Alternatively as Nort suggested, where the current Rundle St U-Park is located.

- Victoria Square station: on the southern portion of Vic Square, adjacent the existing tram stop. Allows easy transfers.

[Westside]

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

Why couldn’t they build escalators within that 25m diameter shaft? Yes it will have to zig zag multiple times down to the platform level (much like escalators in a department store) but surely there would be room for it and much better than elevators only.

Also more simple than excavating a separate shaft for an escalator.

What? How else do you get between the surface and the rail tunnel? The 25m wide tunnel is horizontal at many metres below the surface, you then use small tunnels to connect between that and the surface.

Having said that, cut and cover is still by far the cheapest method, with possibly some small Tunnel-Bored segments in-between where needed. You just need to carefully locate stations along existing roadways or empty (or cheap to demolish) lots. Even in Sydney, they saved a heap of $$ for their NW metro by using smaller tunnels (to accommodate only single-deck trains, not the traditional double-stack). So I wouldn't assume that this method is the panacea of options out there. Having not opened some 17 years later is testament to that.

[1NEEDS2POST]

The higher (or deeper) you go, the more advantage lifts have. Escalators run at a fixed speed, which is slow in Western litigious countries. Lifts can accelerate and decelerate, which gives them an advantage over longer distances.

Having said that, cut and cover is still by far the cheapest method, with possibly some small Tunnel-Bored segments in-between where needed. You just need to carefully locate stations along existing roadways or empty (or cheap to demolish) lots. Even in Sydney, they saved a heap of $$ for their NW metro by using smaller tunnels (to accommodate only single-deck trains, not the traditional double-stack). So I wouldn't assume that this method is the panacea of options out there. Having not opened some 17 years later is testament to that.

Once a TBM is up and running, its costs are small. Cut and cover is cheaper, but if you can't use cut and cover for the whole route, that's when the costs escalate. I can't see how we can have corners in a CBD rail tunnel that are cut and cover, unless the corners are in the parklands.

Smaller tunnels are cheaper, but we have a legacy system with a loading gauge designed for full sized trains. How do the costs of a TBM scale with diameter? If small tunnels are much cheaper, then why stop at metro standards? Build it as a low floor tram with Adelaide's 2.4 m wide loading gauge.

[ml69]

Have recently been holidaying in Singapore, and using their brilliant MRT Metro system, widely-regarded as among the best systems in the world.

Clearly our rail system is light years behind the world’s best. But it got me thinking about the importance of a CBD rail tunnel to link our rail lines together, and how it would be a real game-changer for public transport in this city.

The ability to quickly and easily to get your desired CBD location cannot be under-estimated. Whether that be North Tce/Adelaide Oval, East End/Rundle Mall or Vic Square/Central Market. It considerably adds to the quality of life within a city.

[Ho Really]

Have recently been holidaying in Singapore, and using their brilliant MRT Metro system, widely-regarded as among the best systems in the world.

It's great that your eyes have been opened. It's not just the MRT, it's how Singapore goes about designing their city. It runs on several levels. Below ground, on the ground and above the ground. We need to emulate this here. The sooner the better.

Clearly our rail system is light years behind the world’s best.

Currently it is probably the worst in Australia, but it can easily become the best.

But it got me thinking about the importance of a CBD rail tunnel to link our rail lines together, and how it would be a real game-changer for public transport in this city.

The ability to quickly and easily to get your desired CBD location cannot be under-estimated. Whether that be North Tce/Adelaide Oval, East End/Rundle Mall or Vic Square/Central Market. It considerably adds to the quality of life within a city.

Got more to say about this, but I'll do that later...

Cheers

[Eurostar]

Now that the Seaford and Tonsley Lines are electrified the State Government should be selling the land above especially in areas such as Ascot Park, Oaklands, Hove (once grade separation is done), Noarlunga Centre, Seaford. A underground city rail loop with stations in the right places could help boost areas too.

[Norman]

Now that the Seaford and Tonsley Lines are electrified the State Government should be selling the land above especially in areas such as Ascot Park, Oaklands, Hove (once grade separation is done), Noarlunga Centre, Seaford. A underground city rail loop with stations in the right places could help boost areas too.

The cost of putting the train lines underground will be much higher than any resale value of development above the train line. They should focus on increasing density near the stations instead.

[1NEEDS2POST]

Now that the Seaford and Tonsley Lines are electrified the State Government should be selling the land above especially in areas such as Ascot Park, Oaklands, Hove (once grade separation is done), Noarlunga Centre, Seaford. A underground city rail loop with stations in the right places could help boost areas too.

The cost of putting the train lines underground will be much higher than any resale value of development above the train line. They should focus on increasing density near the stations instead.

This, it's crazy that most stations are surrounded by single-family detached homes. All houses within 400 m of every station should be allowed to build granny flats. That's the simple, easy solution to increase density around stations right now.

The only place where real estate is valuable enough to build over the top of a railway is in the CBD.