Penn Central was only one of many railroads to use a subsidiary RR with better credit to lease or buy equipment at a cheaper rate than the parent company could obtain. ( No surprise there, given PC's shaky finances.) Penn Central would also use PCA and PCB reporting marks on some leased equipment so it could be easily located should the parent RR go toes up. General Foods leased an order of 50 foot insulated boxcars for Erie Lackawanna's use, with the cars painted General Foods' corporate blue. This also explains Espee's habit of buying diesel locomotives through their Cotton Belt subsidiary, including many Tunnel Motors lettered for the line that had no tunnels !!!
I recall also cases where the BIG railroad kept a smaller merged RR " alive " for tax or franchise purposes, as Epsee did with Central Pacific.