Hits on a pet idea of mine:<p>We have a major issue with rail transportation in the US. It's most useful in cities in a grade-separated form, but it's simultaneously the hardest to build in cities in a grade-separated form. The number of existing pipelines, power lines, traffic reroutes, building permits, and private property consents required to check out grows to dizzying levels of complexity.<p>One way to bypass this is to dig deep, <i>deep</i> tunnels. Tunnels far enough down that surface settling doesn't occur, tunnels far enough down to bypass skyscraper pilings. To do this well, though, you need to construct as much of each station as possible in the tube itself, and only sink shafts down to that level, not whole horizontal rooms.<p>You can do that with a ~20m diameter TBM. You buy this monster of a machine for an exorbitant amount of money, and in exchange you get to leave the walls that it constructs in place, except for some vertical elevators and a vertical stairwell directly to the platform; No blasting, no extensive bit-by-bit excavation, no surface trenches, no access tunnels, no adjusting to separate mud and soil and rock. Just two tracks in a big tube with a bunch of space in between them, and maybe a second level for another pair with an express line.
Looks pretty impressive and to think some people say tunnelling is boring! It is and it isn't. :)<p>In other news, Crossrail finished tunnelling today. Not as long as this but still a big project.<p><a href="http://www.crossrail.co.uk/news/articles/prime-minister-and-mayor-of-london-celebrate-completion-of-crossrails-tunnelling-marathon" rel="nofollow">http://www.crossrail.co.uk/news/articles/prime-minister-and-...</a>
What a strange article. Is there a translation or cultural context? The part about the Japanese "los[ing] face" or the reference to Russian civic culture are two of many puzzling bits.
Meanwhile in London:<p>Crossrail tunnel already smells of urine<p><a href="http://www.thedailymash.co.uk/news/society/crossrail-tunnel-already-smells-of-piss-2015060498925" rel="nofollow">http://www.thedailymash.co.uk/news/society/crossrail-tunnel-...</a>
It's a great project, but that article is a bit deceptive. The breakthrough video is from 2010. Official opening is a year away. The tunnels are finished, with track, power, and signaling almost ready.[1] But the connections to the railway system at both ends aren't ready yet.<p>As tunnel projects go, it was a long drive, but not an unusually difficult one. Mostly hard rock, some water problems, but not too much water. Many tunneling projects are more about keeping the water out and the roof supported than digging.<p>Surprisingly, it was just a 4 TBM job, two tubes cut entirely from the ends. Although there are several vertical shafts down to emergency stations, those were not used as TBM starting points. Each TBM had to grind forward for almost 14 years.<p>[1] <a href="https://www.alptransit.ch/en/status-of-the-work/railway-infrastructure/" rel="nofollow">https://www.alptransit.ch/en/status-of-the-work/railway-infr...</a>
I see a countdown timer at the Bellinzona station. Edit. I think the first (regular PASSENGER) train's going to run through the tunnel sometime in Dec 2016.
"...the Gotthard base tunnel 'broke all the rules' and the excavation was finished nearly a year ahead of schedule."<p>I'd like to know more about this.
If they include the Koralm Tunnel on the list, which is under construction, they could as well add the Brenner Basis Tunnel (<a href="http://en.wikipedia.org/wiki/Brenner_Base_Tunnel" rel="nofollow">http://en.wikipedia.org/wiki/Brenner_Base_Tunnel</a>) :)<p>When completed, it will be the world's second largest tunnel, only shorter than this one.