A practical step that would not be excessively costly would be to standardize the three types of rail in the US - local tram, commuter, and intercity/high speed (fun fact - depending on your definition of high speed rail current Amtrak trains can hit that, as on correct track and with positive train control they can do 125+ MPH).

If it's standardized it will be easier to make sure you can develop it piecemeal.