Other People's Rail: Amtrak, commuter rail, rapid transit news & views outside New England

It also sounds like they are being very optimistic about the ability to tunnel directly under existing century old tunnels and stations without causing damage, by using the ground freezing techniques. The reason the design went very deep along 125th Street is because shallow conditions for tunneling are really poor. Shallow tunneling sounds like a recipe for years of damage mitigation.
The Effective Transit Alliance suffers from a perfectionism complex in their technical recommendations. Sort of like how TransitMatters' Regional Rail traffic modeling relies on heavily suspect hyper-aggressive performance expectations with threadbare safeguards...but plied on a more grand scale across all of the ETA's rail advocacy. I guarantee they glossed over the engineering challenges of digging under old streets. Which sucks because there's copious opportunities for cost savings while delivering a better product than the MTA's insane elevator-city access strategy for Phase 2...but the more careless aspects of the ETA's work are ripe for having holes poked in it by skeptical institutionalists clinging to their Not Invented Here ways.
 
They're advocating cut-and-cover, not TBMs.
That's not really correct. They still recommend using TBM for the tunnel, but much more shallow. They do recommend cut-and-cover for the stations, which would be possible by running the TBM closer to the surface. That would be a heck of a lot cheaper than the current plan of mining deep stations.
 
That's not really correct. They still recommend using TBM for the tunnel, but much more shallow. They do recommend cut-and-cover for the stations, which would be possible by running the TBM closer to the surface. That would be a heck of a lot cheaper than the current plan of mining deep stations.
It "might" be a lot cheaper than mining deep stations -- depending on the success of underpinning century old infrastructure right over the proposed new stations.

Or it might lead to the closure of multiple other lines for several years of repairs. Big roll of the dice.
 
Some crazy nimbyism going on outside chicago where a suburb on the way to ohare is trying to block a new train line between ohare and downtown which is going to just barely pass through their town and theyre doing everything possible so it essentially wouldnt affect the residents at all but of course theyre still furious. Insanity.

 
Some crazy nimbyism going on outside chicago where a suburb on the way to ohare is trying to block a new train line between ohare and downtown which is going to just barely pass through their town and theyre doing everything possible so it essentially wouldnt affect the residents at all but of course theyre still furious. Insanity.

CAVEAT: The outfit that's pitching this smells a whole lot pie-in-the-sky and just a little bit scammy.
 

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