Twenty-seven miles east of Hollister in the heart of earthquake country is where California High Speed Rail could meet its Waterloo.It is where a problematic 13.5-mile tunnel starts that skirts the northern edge of San Luis Reservoir and drills into a geological mixture of sandstone riddled with weak shale known as the Franciscan Complex. It was the result of the Pacific Plate slipping under the North American Plate to push what is now known as the Diablo Range skyward.In spots the tunnel will need to run 1,000 feet deep. This is where the high speed rail authority wants to construct the country’s longest and most complex transportation tunnel.The cost of crossing beneath Pacheco Pass was never fully vetted before the high speed rail authority made what in retrospect is looking more and more like a fatal decision to not go over the somewhat lower Altamont Pass instead.The rail authority pegged the cost of building the 54-mile segment from Chowchilla to Gilroy at $5.6 billion.