Adelaide's Premier Development and Construction Site
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https://mail.sensational-adelaide.com/forum/viewtopic.php?t=1327
An above ground structure will always be far cheaper than a tunnel... less than half the cost.Goodsy wrote: ↑Thu Nov 01, 2018 3:30 pmWould elevated lines in the city even be cost effective these days? you could make the case that elevating a line down King William rather than cut and cover would have been preferable back in the day. But surely a TBM chugging away underground would be cheaper
Away from the CBD it would be, but surely the cost of the disruption caused to the businesses on King William would bring that cost on parml69 wrote: ↑Fri Nov 02, 2018 5:16 amAn above ground structure will always be far cheaper than a tunnel... less than half the cost.Goodsy wrote: ↑Thu Nov 01, 2018 3:30 pmWould elevated lines in the city even be cost effective these days? you could make the case that elevating a line down King William rather than cut and cover would have been preferable back in the day. But surely a TBM chugging away underground would be cheaper
Would such a structure in King William Street ever be allowed? Given the huge fuss over road relocations due to the O-Bahn tunnel, I imagine pylons and an elevated railway over King William Street would need a lot of support. I'm not sure if I can see that.Goodsy wrote: ↑Fri Nov 02, 2018 8:15 amAway from the CBD it would be, but surely the cost of the disruption caused to the businesses on King William would bring that cost on parml69 wrote: ↑Fri Nov 02, 2018 5:16 amAn above ground structure will always be far cheaper than a tunnel... less than half the cost.Goodsy wrote: ↑Thu Nov 01, 2018 3:30 pmWould elevated lines in the city even be cost effective these days? you could make the case that elevating a line down King William rather than cut and cover would have been preferable back in the day. But surely a TBM chugging away underground would be cheaper
I see it as a pointless thought-bubble. Why bother to care about our heritage facades if they would be obscured by an aerial railway line anyway.rubberman wrote: ↑Fri Nov 02, 2018 9:50 amWould such a structure in King William Street ever be allowed? Given the huge fuss over road relocations due to the O-Bahn tunnel, I imagine pylons and an elevated railway over King William Street would need a lot of support. I'm not sure if I can see that.
If you don't need to bore, don't. That's still a mantra used today. TBMs are still so much more complicated and expensive than cut and cover. Even New York's most recently opened line, the Second Ave subway (part) used multiple construction methods where appropriate:claybro wrote: ↑Thu Nov 01, 2018 6:01 pmAgreed. But if they have to go to the expense of getting in a boring machine for some sections, it would be better to keep it on the whole project? Bearing in mind, there will be a significant difference in the depth of bored tunnel as opposed a cut and cover tunnel, and lining these up will add to the cost and difficulties.
That is just not true. Tunnel linings will ensure structural integrity. TBMs are best suited to the conditions they're designed for. There are three basic designs of TBM: EPB (earth pressure balance) for tunnelling through clay, Slurry for tunnelling through sand, and Hard Rock. Hybrid TBMs (essentially a 21st century innovation) bring the available choices up to seven, but varying ground conditions don't always require them — EPB TBMs can use gelling agents to tunnel through sand, and can cope with some rock. Our limestone layer wouldn't be too big an obstacle for an EPB TBM.Westside wrote: With Adelaide's soft sandy base, I'm not sure how viable a TBM is anyway. TBMs are best done in rock rather than sand/soft soil for structural integrity, so a bored tunnel may need to be at quite a depth!
Sydney has long had lines going through it as well as the loop (which is far from terrible as passengers all have the option of changing trains at Central). Melbourne has the option of more through services, but stupidly chooses not to use it.Oh, and picking up a previous comment, rail loops are just terrible, full stop. One single line will add great cross-town connections. What happens in a loop is you bring great inefficiencies near the join. For example, a loop through the city and then return north via Mile end is great for the incoming passengers, but passengers wanting to head north from ARS have to travel east, south, west then finally north, virtually all the way around the loop just to leave the city.
Both Melbourne and Sydney loops are terrible for this reason and both cities have new projects to send lines directly through the city.
Interesting list of projects with multiple methods employed. Be interesting to see how they cope with joining the various sections, getting the TBM into place then removing it ETC. different depths and other issues.Westside wrote: ↑Fri Nov 02, 2018 12:33 pmWith Adelaide's soft sandy base, I'm not sure how viable a TBM is anyway. TBMs are best done in rock rather than sand/soft soil for structural integrity, so a bored tunnel may need to be at quite a depth!
Oh, and picking up a previous comment, rail loops are just terrible, full stop. One single line will add great cross-town connections. What happens in a loop is you bring great inefficiencies near the join. For example, a loop through the city and then return north via Mile end is great for the incoming passengers, but passengers wanting to head north from ARS have to travel east, south, west then finally north, virtually all the way around the loop just to leave the city.
Both Melbourne and Sydney loops are terrible for this reason and both cities have new projects to send lines directly through the city.
Sort of dog legs loop + direct tracks into Adelaide Station...weird mixture of commuter station terminus (a dead end) and a through metroChillyPhilly wrote: ↑Mon Oct 29, 2018 5:51 pmFound on page 122 of the Integrated Transport and Land Use Plan (ITLUP). It's still available to view online - make the most of this before the Liberals quietly delete it and replace it with a 'page not found'.
Inner Adelaide:
CBD, including underground rail loop:
It would be similar to Perth train stationPeFe wrote: ↑Fri Nov 02, 2018 7:15 pmSort of dog legs loop + direct tracks into Adelaide Station...weird mixture of commuter station terminus (a dead end) and a through metroChillyPhilly wrote: ↑Mon Oct 29, 2018 5:51 pmFound on page 122 of the Integrated Transport and Land Use Plan (ITLUP). It's still available to view online - make the most of this before the Liberals quietly delete it and replace it with a 'page not found'.
Inner Adelaide:
CBD, including underground rail loop:
It looks like it supports loop services from/to the south, and probably can handle north-south through services, but others would generally be at the existing station. north and northwest services from Adelaide would be odd if they could be on either ex-Seaford services on the loop or terminated services from the far end of the station.claybro wrote: ↑Fri Nov 02, 2018 9:24 pmAlthough impossible to tell from such a vague map, it does not appear to be a proper loop, more of a u shaped through tunnel. It looks like a good option for Adelaide as it covers the east end as well, gives access to the Mall(east end) and yet avoids the pitfalls as discussed of a circular loop. As for Adelaide station, I believe the underground will be a different station, but adjacent to the existing station linked by an underground walkway, as someone mentioned, similar to the Perth setup. I can say it is quite a walk via the underground link from Perth surface station to Perth underground and they don't really feel linked. I think in Adelaides case a station directly under north Terrace and linking via the existing pedestrian underpass would be a much better setup.
