GREEN GOAT RailPower Technologies Corp.'s Green Goat diesel-electric "switcher" was a promising technology because it is powered primarily by batteries (even when it idled) and employed its diesel engine only to recharge the batteries. Unfortunately, the Green Goat's batteries are known to have caught fire, forcing RailPower to recall, retrofit and update 59 units of the locomotive.
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Trains have long been a more fuel-efficient way to haul freight than trucks, but now the federal government's amped up support in the alternative energy arena may help "the iron horse" go even greener with hybrid locomotives and other advances.

Although large freight railway traffic (measured in carloads) is down 19 percent this year due to the recessed economy, it grew 47 percent between 1990 and 2007, and railroads have been more fuel-efficient than trucking for at least the past few decades, according to the Association of American Railroads.

The average train in 1980 used four liters of fuel to move one ton of freight 380 kilometers, and by 2007 the average increased to 700 kilometers, or three times the fuel efficiency of a truck, says Steven Forsberg, general director of public affairs with BNSF (Burlington Northern Santa Fe Railway) in Fort Worth, Tex.

New hybrid locomotives are designed to do even better, trading on the same technologies found in today's hybrid automobiles. General Electric uses a regenerative braking technology in its trains similar to that found in a Toyota Prius. The Mercedes-Benz Citaro fuel-cell transit bus set the stage for railroad energy-efficiency systems being created by hydrogen fuel-cell technology company Vehicle Projects, Inc. in Golden, Colo. And the Chevrolet Volt is the basis for an ethanol-based hybrid under development by Milford, Ohio–based Alternative Hybrid Locomotive Technologies, Inc. (AHL-TECH).

"The use of hybrid locomotives can reduce locomotive exhaust emissions and energy consumption, while providing an adequate or equitable amount of power to operate trains," says Warren Flatau, a spokesman for the U.S. Department of Transportation's (DOT) Federal Railroad Administration.

View a slide show featuring green train technology

Pros and cons
The challenges that arise in developing hybrid locomotives—such as power density and durability—are the same as in cars, but on a bigger scale because of the heavy load and harsh vibrations associated with rail freight, says Glen Merfeld, manager of GE Global Research's chemical energy systems lab.