The U.S. is increasingly awash in natural gas, so it's natural to consider it as a potential vehicle fuel.
From passenger cars to long-haul trucks, both compressed natural gas (CNG) and refrigerated liquid natural gas (LNG) are being eyed as a replacement for diesel fuel and gasoline.
Now, natural gas may make the leap into another kind of wheeled vehicle: railroad locomotives.
Freight railroad BNSF announced this week it would convert a locomotive to run on LNG, to test the concept in real-world use.
Matt Rose, the railroad's CEO, told the Wall Street Journal that the test "could be a transformational event" for the company and the industry.
Among the challenges will be building new tanker cars to carry the fuel, new fuel depots, and training of railroad workers--as well as signoff from regulators at the historically conservative Federal Railroad Administration.
Nonetheless, BNSF has an aggressive timetable: It hopes to have a pilot train running this fall and, if it proves successful, to begin retrofitting existing locomotives a year later.
A conventional diesel-electric locomotive costs roughly $2 million; early conversions might add another $1 million to that price, though the cost would fall substantially in volume.
But the investment would be more than made up in cost savings on fuel, since the price of U.S. natural gas is expected to stay low for many years into the future with increased production.
A gallon of diesel fuel runs about $4 today, while an amount of natural gas with the same energy content costs less than 50 cents, according to the Wall Street Journal.
And natural-gas fueling offers two additional benefits: Trains would have to stop less frequently to refuel, and their emissions of particulates and other pollutants would be cut drastically.
2012 Honda Civic Natural Gas
Ironically, BNSF hauls freight and natural resources that include both grain and oil from North Dakota to other parts of the country.
Using domestically-sourced natural gas to haul domestically-produced oil would likely be a first in the rail-freight business.