Dive summary:

• The Obama administration loves high-speed rail, and rail construction means work for contractors, but a proposal for a Las Vegas-Los Angeles line has been shelved because of something else that federal transportation officials love – requiring everything to be sourced in the U.S. when federal dollars are involved.
• The problem with applying the rule to the rail is that Express West couldn't likely buy American because the U.S. does not have the industry to supply everything for high-speed trains.
• There may well have flaws in the plan as it had been devised, but it never got that far in the Department of Transportation.

From the article:

That makes meeting the Buy America provision "not commercially possible" in this particular case, counters XpressWest in a statement posted on its website.