I think CN has traffic agreements with several RR's in PA and Ohio (W&LE for one, maybe B&P). They might be holding onto the B&LE for that reason... to funnel traffic up and down the B&P to Buffalo to CN home rails.
They might like the idea of handling the ore traffic from the DM&IR to the B&LE via the great lakes. They might (big might) be able to steer traffic to the B&LE.