High-speed rail service through downtown San Jose will be above ground, an independent consultant determined in November.

Exeltech Consulting of Lacey, Wash., determined technological limitations of building amid the aquifer and worker safety would get in the way of constructing an underground station.  Such a station would cost between $5 billion and $8 billion – which far exceeds the high-speed rail budget.

High Speed Rail is advancing two alignments for environmental clearance.  One is the seven-story-tall aerial viaduct that the Downtown Association believes would mar the aesthetic look of downtown and create a barrier similar to the Highway 87 elevated structure.

An at-grade solution is also in the mix and part of the environmental review, due by the end of 2019.  The track alignment is also being considered by Benthem Crowel and Arcadis, which is assigned to integrate high-speed rail and BART into the next-generation San Jose Diridon Central Station plan.