If it has 4 axles, it isn't an SD-45. SD-45's were/are 6 axled desiels...a bit large for a trainset. Trainsets usually include 4 axled desiels such as F-units, GPs, or switch engines. Do you have a particular plan for modelling the Chessie System? (such as a strong reason to model the late '60s or a particular local?) You also might want to take a stroll down to the Cincinnati Railroad Club's Tower A library (there's a sign & an elevator next to the Omnimax entrance at Union Terminal...open Saturdays 10-4 and most weds after 8)...they have many, many books. I highly recommend C&O Power Steam & Desiel Locmotives of the Chesapeake and Ohio Railway 1900-1965. The Hamilton Co Library doesn't have it (although my home county's library did), but Middletown or others might too....I know the CRRC has it in their library.
bigsteel, I live in Clifton Heights (I bought a home near UC for grad school)...I can hear squeals from Queensgate daily...shame the city didn't ask the C&O for one of their unique engines to display (L-2 Hudson, big mikado, 0-10-0, T-1).