FWIW, I boarded a greenbush train yesterday evening from Tack 12. There were two Kelolis employees scanning tickets by the end of the platform. I asked the guy who scanned mine if he knew where the new faregates were going, and he said: “I don’t know exactly. Somewhere in-between [gesturing from where we were standing and towards the area under the new archways]. I don’t know exactly.”
So while not exactly confident or exact information, I do think this indicates that the faregates will be outdoors and not inside the lobby like I predicted above.
(Also, these diagrams are a great find, Sltin)
Edit: perhaps I’m missing something, but if the fare gates already accept MBTA and Amtrak ticket barcodes, would it really be much more of a stretch to have them accept bus ticket barcodes too? And wouldn’t this allow you have the bus terminal-rail platform escalators behind fare control - as long as you add some faregates upstairs?