I just discovered a most interesting "sign" for sale on e-bay at:
Although the seller apparently doesn't know what it is, it is probably the fiberglass herald PC put on the front of and sides of the #200 series cars that operated out of Philadelphia. Definitely the thing to put on the wall above your PC model layout.
I've considered bidding on this (and still may) -- except I already have one. My example was from the front of the car. Since the one for sale is probably smaller, it is probably from the side between the window and the door.
San Antonio, TX