The mention of Foley Brothers Construction made me remember that the firm was an early user of a diesel locomotive. It bought a 600HP (double engine), 100-ton box cab locomotive from IR-GE in 1929 which was delivered in January, 1930, for use at Colstrip, Montana.
This locomotive is now in the collection of the California State Railroad Museum -- having recently obtained it from the Portola RR Museum. This is the one remaining 600hp locomotive of the ALCo-IR-GE or IR-GE box cab design -- and it still has the IR engines!
If you are interested here are a couple of links to more information:
http://www.cnwhs.org/ageir/ge_roster.html
http://sbiii.com/boxc110p.html
Brian Norden