Forget high speed rail, where's the commuter trains? It seems ridiculous that in most US cities public transit is mostly non-existent. Traffic is bad in most major US cities you'd think people would be jumping for this as urbanization increases.
It doesn't work if you don't have that central density & transit. It doesn't generally work in the opposite direction either. (Urban dwellers to suburban jobs.)
Caltrain is currently running 30-year-old diesel locomotives and 30-year-old passenger carriages on many of its trains, because they have no funding to get more modern equipment or electrify the line. Minor breakdowns have been increasing for a while, with occasional major problems (like last week when they had a fire in one of the locomotives during the evening rush hour).