As a few people said previously, that old Seneca Mall site is REALLY small. Now if you took out the tracks and cleared the adjacent plaza, maybe you have enough room. You could probably negotiate with Wegmans to move also, it is an older store.
I doubt you see trains to the stadium. Amtrak would not dedicate the equipment for a once a week every other week trek off its planned routes. The same reasoning you don;t see trains to OP. The West Seneca tracks are severed also, but farther down the line in Blasdell. They are only used now for car storage