421 pulls the 4 empties from Continental Can under an old Pennsy Signal bridge that once guarded the entrance to the Valley Yard (now just a single track main) from points south on the Valley Line of the Pennsy/Conrail like Emlenton, Foxburg, Kittanning, Kiski Yard on the Conemaugh Line, and downtown Pittsburgh on the current Allegheny Valley RR's Valley Branch.
