I receive e-mails from the American Society of Animal Science and this story was under their animal headlines- I thought it was pretty cool, especially since it had to do with beef!
For the past year passengers riding on the Amtrak Heartland Flyer from Oklahoma to Texas have been fueled by a mix of beef tallow (fat) and diesel fuel. Beef tallow is also used in making soaps. During the year of testing officials discovered that the fuel blend met industry standards, engine wear was less than usually expected and emissions were below federal limits.
You can read the full article here