It's still active for a lot more than just that. Export locomotives, hundreds per year, are built there. The newer plant in Forth Worth is only used for domestic production.
There may come a time when GE sells Erie but it's not going to happen right now.
The trend in US railroading right now is for railroads to contract this stuff out to private companies. It would be very odd for a railroad to make such a huge and expensive commitment to keeping it in-house by literally purchasing a locomotive factory.
Pan Am Railways — Boston & Maine/Maine Central — Delaware & Hudson
Central Maine & Quebec/Montreal, Maine & Atlantic/Bangor & Aroostook
Providence & Worcester — New England — GE Locomotives