MLB Subway Sign with Field Dirt Pittsburgh Pirates. This vintage-style Subway Sign is a must-have for any Pittsburgh Pirates fan! Rather than showing the stops along a subway line, this unique sign details stops along the Pirates' history. Comes in a handsome frame, and measures 1" Thick. Features dirt from PNC Bank Stadium, authenticated by the MLB! Guaranteed authentic by Steiner Sports. Materials: Mica, Plexi, Glass, Dirt.