>Although 2.2 miles is a non-grateful length, if it must be diesel operated… even if the diameter were set for a later 360 km/h operation, extensive ventilation is needed, making operation more expensive. If it could be strictly electric, there would be no need for ventilation at all (and as I understand the situation, there is not much rock above the tunnel, meaning not much thermal load).

Don't forget, BNSF and Pacific Sun still have trackage rights to operate freight. There is little doubt in my mind that it is inevitable that this line will be electrified due to the amount of passenger service, but some stumbling blocks may be north of Fullerton to San Luis Obispo (BNSF and UP). Then again, I would not be surprised if environmental/political pressure is put on BNSF to electrify at least Barstow-Los Angeles to the harbor, as well as Barstow-Mojave and Bakersfield-Stockton. UP would have to electrify Reno-Roseville-Bay Area; Roseville down the valley over Tehachapi to COlton and the harbor; maybe Colton-Yuma too? This should give them plenty of territory to try out their regenerative braking.

I grew up in San Diego County, and along the north coast the soil is real interesting. It's like a sand that acts like it wants to be sandstone, but isn't even close to being that hard. And don't forget - there are several earthquake faults involved - I beilieve one through the tunnel area.