Introduced in the fall of 1976, the C30-7 marked the start of a new generation of motive power from General Electric. Its 16-cylinder diesel engine delivered 3,000 horsepower, making it an ideal choice for heavy freight service. Production continued through 1985, and most are still in service today. As delivered, the locos sported two smaller windows on the cab sides. New rules adopted in 1980 required all windows to be projectile resistant for safety, and many road chose to fill the openings with sheet metal rather than install new glazing. Units built after the rules change came only with standard side windows. Models are offered with early (187-471 series) or later style (187-482 series) cabs.