OKLAHOMA CITY – On Oct. 31, Amtrak officials successfully tested a mix of beef tallow and diesel fuel to power a passenger train's 3,200-horsepower engine, according to The Associated Press. After a yearlong test on the rails between Oklahoma City and Fort Worth, Texas, an evaluation found the fuel blend met industry standards, engine wear was limited and emissions were below federal limits for the type of engine using it.

The railroad was able to replace about 35,000 gallons of diesel with a locally produced renewable fuel during the test, said Roy Deitchman, Amtrak's vice president of environmental, health and safety vice president.

Tallow often is used to make soap or animal feed. Previous tests found engines running on a biodiesel mix had lower emissions, but further testing was needed to ensure its gaskets didn't wear prematurely with an animal-based product in the engine. Amtrak said the blend resulted in no more wear than usual.

Presented last week at a railroad environmental conference at the University of Illinois at Urbana-Champaign, the results also showed less pollution.

Amtrak used a $274,000 federal grant from the Federal Railroad Administration and worked with the Oklahoma Department of Transportation to test the fuel in its locomotive.