Am Trak is more fuel-efficient than an AirLine, but less efficient than an Inter-City bus (and only matches the AutoMobile). However, as an Office of Technology Assessment (OTA) report states, "[T]he energy intensity of the vehicles tells a limited story, since a great deal of energy is imbedded in each mode's capital infrastructure and expended in ancillary activities such as powering stations, repairing roadways and guideways, and so forth."(6) Numbers on imbedded energy appear to be unavailable, complicating comparisons of modes on the basis of energy consumption. (Energy Accounting)
http://en.wikipedia.org/wiki/Fuel_efficiency_in_transportation - shows trains as 10x the efficiency as the automobiles.