There's capital cost inflation in all big US infrastructure investment projects, for similar reasons though not to the same extent that infrastructure project costs are often inflated in Greece ~ the yellow belly surplus suckers must be fed. In the typical California case, a severely understaffed Joint Powers Authority has a skeleton staff and all major project management must be done by contractors, who systemically overbudget and plan to overbuild.

But its not as severe as the headline $68b price tag makes it sound, since that is the Year of Expenditure budgeting that the US DoT insists upon. The discounted present value is projected to be around $53b.

The Initial Construction Corridor, through the Central Valley, is around $6b, for 210km of HSR corridor, less electrification.

The most expensive section is the descent into the LA Basin, either over the Tejon Pass, or on the preferred corridor, following the population, over the Tehachapi Pass. The second most expensive section is the traverse from the Central Valley to the Bay Area. One might imagine that improved project management could trim another $5b or $10b out, but a SF Bay to LA Basin Express corridor plus upgrades to provide Express Interurban access to downtown San Francisco and downtown LA is going to cost north of 2012 $40b, in any event.

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.