Graeystone's correct.
But in addition, in blue cities and states, ANYTHING can be used to feed the tax & spend monster. Extra points if it's something central to lib dogma, such as getting people out of their cars and into mass transit.
As it turns out, high-speed rail projects allows a lib jurisdiction to level up from wasting millions to wasting billions, or (in California) even hundreds of billions. Those kinds of projects are large, complex, and so long and involved that there's no possibility of public awareness about what's going on. Add a compliant MSM, which will NEVER inform the taxpayers how they're being ripped off, and monstrosities like this is the inevitable result.
Keep in mind that was $11 BILLION for a single glorified bridge. California democrats aren't about to declare a wasted-money victory and stop there. Their high-speed rail fantasies will continue - at what, $10-$30 billion per mile?! - until the state's and the nation's financial systems have so thoroughly crashed and burned that it's absolutely impossible to continue.
Then California's high-speed rail network will finally end up what it's always been: from nowhere to nowhere. And just as you first said: a failed project, like in so many other places.