Posts Tagged ‘tunnel’

Robert Moses Resurrected

Who would have thought that 1950’s-style highway planning would be back — only this time in the form of 224 mph high-speed trains? Draw two points on a map, a line in between, and never mind what neighborhoods are in the way of progress:

State officials looking to shoot 220-mph bullet trains through densely populated neighborhoods in San Jose — with the least resistance from residents — are shopping four alternatives to the original route along existing Caltrain tracks.

And here is the map of the alignments (click to enlarge).


Risks of Tunneling
The proposed alignments would run underground. In any high-speed rail project, digging tunnels underneath urban neighborhoods is something to be avoided if at all possible. Not only is it expensive and disruptive, it is also supremely risky. For example: one of the worst civil engineering disasters in the UK was the collapse of the Heathrow Express tunnel. The collapse caused severe damage to buildings at the world’s busiest airport. And it was dumb luck that one of the world’s busiest subway lines wasn’t knocked out too. Similar types of disasters have happened in Cairo and Los Angeles.

Don’t Dig If You Don’t Have To
When high-speed rail technology was developed some 4 decades ago, the critical requirement was compatibility with existing steel-wheel rail infrastructure. That way, planners avoid complications of building new tunnels and ROW into urban centers.

Ironically, San Jose Diridon station has 3 railroad ROW’s running north through Fremont, and another running south. The one running South is, we now know, off limits because of UP freight requirements. But looking north, the VTA owns the ROW running north to Fremont and all the way to Niles (for route through Altamont). Moreover, the other two ROW’s are also entirely feasible, as is the CHSRA preferred alignment on I880 for their (purely theoretical) Oakland spur.

Of course, none of these cost-effective solutions will work if your main objective is building new rail line out into open space and wilderness for the benefit of real estate speculators who bought up ranchland way out past Gilroy…

Environmental Impacts of Tunnels
Lately, the idea of buildings tunnels along the Peninsula for high-speed rail has been seen as bringing certain environmental benefits. Certainly for neighbors living along the line, a tunnel does not have the visual impacts that a surface or aerial line would have. But in other areas, one should not automatically assume tunnels are environmentally benign. While tunnels mitigate noise, they may actually amplify vibration. There are also hydrology challenges to consider. The San Jose downtown area sits in the middle of a major watershed that is already severely degraded.


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