The Bethlehem Steel plant in Steelton, PA would ship many carloads of pipe on Conrail train ESPI on ex MDT 89' flatcars. I recall those trains running almost daily for several years starting in the late 80's. If Western PA works, there was the USS National Works in McKeesport, PA. They made seamless and welded pipe of all different sizes. The plant was served by the McKeesport Connecting Railroad (then URR), the PRR (then PC, then CR) and the B&O (then CS, then CSX). The National works was a fully integrated mill. Towards the end, when the hot end shut down, they got sheet from Irvin to weld and rounds from Duquesne for seamless. When USS left town in 1987, it was taken over by Camp Hill Corporation. In a twist of fate, USS bought it back in the 2000's. Then, when demand fell, they shut it down again. Durabond currently owns the pipe operations and is making pipe there today. Thanks.
Jeff