I'll say it right off the bat. This model is a foobie. 2415 did not look like this in service with CR, but the model was too nice to pass up.
That being said, I really like the way this one has turned out.
It's a Lifelike (pre-Walthers) C424 that was originally painted as PRR 2415. I left the number alone, but heavily weathered the unit and applied CR decals over the old PRR keystones. In some locations, the old Keystone is actually showing through. This was achieved by using a sharp Xacto knife to scrape away most, but not all, of the printed on logos. Additionally I added a set of ACI labels to the hood sides.
Additionally, I added some Evergreen styrene I beams under the walkways to represent the ALCO frame. This eliminated much of the unsightly "air gap" between the locomotive and its trucks. This distance was correct, but was filled on the prototype, like the model, with a frame that was generally hidden on units from other builders.
This model was weathered with a mix of drybrushing and vodka washes.