This is a guest post by Hans Noelder, a mechanical engineer and cofounder of the Madison Wisconsin Peak Oil Group. This is a link to Hans' blog, where this originally was posted.

Having recently traveled from my home near Madison, Wisconsin to Pontiac, Michigan using rail as much as possible (Metra commuter rail from Harvard, Illinois to Chicago and thence Amtrak to Pontiac) it is clear to me that investments in rail-based transportation could yield substantial environmental and social benefits in this region of the United States – primary among them a massive reduction in automobile-centric sprawl. The synergy between rail transit and dense, pedestrian-oriented urban habitat is especially clear in the Chicago heartland. Her leaders – God bless them! – never allowed their transit system to collapse, much less be systematically dismantled by transit-averse business interests.

However, I am troubled by the various claims I've seen over the years regarding energy consumption and CO2 emissions per passenger-mile for trains/streetcars versus automobiles versus airplanes.