Northeast Corridor as confirmed by diagram comparison that someone mocked up on Twitter soon after it was teased earlier today via TS Facebook page.
Seems to definitely be a portion of the NEC east of New York Penn. The part east of Sunnyside either means a LIRR route or that some freight options are being included with the Northeast Corridor. Will have to wait and see.
Looks like the cat is out of the bag https://steamdb.info/app/577357/ Its Train Sim World Northeast Corridor New York