Quote:
Originally Posted by bvpcvm
Seattle and I think NY are deep bore tunnels, SFO might be substantially cut and cover. I think PDX would also require a fair amount of deep bore tunneling; especially if the tunnel continued through the Lloyd District (which would mean it would have to go under the Willamette; the elevation change would be significant).
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SF's Central Subway is almost completely deep bore as well. In fact, they have two TBMs going simultaneously right now.
I don't think a tunnel needs to start at 13th and Holladay since there's no real impediments to surface MAX until you get to the Convention Center and Rose Quarter. That's where the grade separation becomes crucial and where the portal should be placed. The OCC/RQ station wouldn't even have to be completely underground, just below grade similar to the Sunset TC station but supersized for much larger crowds and many more trains.
Assuming a Pearl District/Union Station next to the Central PO site, a Pioneer Station, and something in the West End/Arts District/PSU vicinity, I don't see why our subway would be more expensive than Seattle's. And certainly not as much as SF's. If you assume 2.5 miles at 750 million/mile, you're looking at 1.875 billion, less than 2 billion.
I think the reason that TriMet and Metro haven't pushed for a Subway yet is they want to build out the network first, the SW Corridor being the last major line in the system (minus various extensions to Vancouver and OC, for example). Expect the Central Subway to be the next major infrastructure improvement/investment once the SW Corridor is complete.