After looking at this web site (briefly) I'm not sure if these engines are actually still available new, or maybe the company just provides replacement parts for the existing Alco and FM engines. They show a variety of other engines, including mostly MAN and Colt-Pielstick engines. It appears that the old FM and Alco engines have generally lasted longer in marine and stationary applications than in locomotives.
http://www.fairbanksmorse.com/
http://www.fairbanksmorse.com/locomotive/
http://www.youtube.com/watch?v=BxlOaBKwlxk&feature=related