So the Pittsburgh and Lake Erie Railroad was purchased by CSX in the early 1990's, the P&LE had lost almost all of its online customers with the collapse of the steel industry in the late 1970s and into the early and mid 1980's.
CSX in acquiring the P&LE used its mainline between Swissvale and New Castle as its mainline rather than use what I call the "nose bleed," mainline of the B&O which headed straight north out of Pittsburgh towards Ellwood City before turning west of New Castle.
So my question is, to what extent was CSX already using the P&LE for most of their trains in the area, the question also applies to the Chessie System and to a lesser extent the B&O.
P.S. I have always thought that the P&LE would have been taken over by the Chessie System or CSX for a mainline, even if the Steel Industry and Manufacturing in the area had not collapsed.