Conrail Breakup
In 1999, CSX Transportation (CSX) and the Norfolk Southern Railway (NS) jointly purchased Conrail on the open market and split up its track mileage and other assets between them. Hence the reporting marks for rail cars, locomotives, and related equipment reverted to NYC (as CSX's portion in tribute to the NYC) and PRR (for the other portion controlled by NS in tribute to the PRR).
The small portion of Conrail that represented trackage that was of interest to both CSX and NS was kept as the remaining Conrail system as the Conrail Shared Assets Operations (CSAO).
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