Its the F9 that came with the Tyco train set I bought as a 13 year old back in the early '70s. The loco was lettered for the Penn Central but originally painted GREEN! It ceased being a useful runner long ago so I removed the motor, turned it into an unpowered unit, painted it a more prototypical black, and gave it some PC decals. It now heads my "Iron City Express" passenger train in front of a powered Athearn B unit painted to match.