The amtrak yearly subsidy is in the neighborhood of 1.3B a year (http://www.heritage.org/Research/Budget/bg2072es.cfm http://www.heritage.org/Research/Budget/bg

The amtrak yearly subsidy is in the neighborhood of 1.3B a year (http://www.heritage.org/Research/Budget/bg2072es.cfm http://www.heritage.org/Research/Budget/bg2072es.cfm) while congress generally passes highway bills which number in the 100s of billions every other year or so. Incomplete story as it's totally ignoring state/local roads and city-level metros -- but that's one data point for you.