Resumen
This paper is a critical review of research on long-distance passenger rail energy consumption that examines the factors that affect the energy intensity of rail, the comparative energy intensity of alternative modes (auto, air and bus), and the sources of discrepancies between different published energy intensity figures. The ambiguities underlying those discrepancies point to a fundamental question about what phenomenon is being quantified in energy intensity analysis, and whether any transport mode can be said to universally have an energy intensity advantage over other modes at all times, places and scales. This ontological question may be as significant as the epistemic conflicts dominating discourses over competing studies and analytical approaches.