Gulf, Mobile & Ohio Alco RS3 1516 and RS2 1504 idle on a diesel house lead track in Bloomington, Illinois in December 1959. No. 1504 was built in 1948, and 1516 in 1950. Both were retired before the GM&O and Illinois Central merged into the Illinois Central Gulf in 1972. Unit 1516 was traded in to EMD on an order of GP38-2s.