LESLEY PROJECT ON TRACK

Lesley University is on the verge of signing an 85-year lease with the Massachusetts Bay Transit Authority for the air rights to the Porter Square commuter rail tracks, meaning it would deck over them and build above.

The move would expand Lesley’s presence in the area — the T stop’s name would become “Porter/Lesley” — and serve to connect Massachusetts and Somerville avenues “for a more coherent sense of neighborhood,” in the words of one attendee at a meeting of the Porter Square Neighbors Association tonight.

The $20 million project started off two years ago as including student dorms, said Marylou Batt, Lesley vice president for administration and university centers and institutes, but those have since gone elsewhere. The space above the tracks now will probably be for academics, with some retail on the ground floor. The retail would probably face Massachusetts Avenue, Batt told the association, and could include a cafe or (to the discomfort of a visiting Porter Square Books proponent) a more public Barnes & Noble university bookstore. The current Barnes & Noble is hidden inside the Porter Exchange, much of it below ground.

Nothing is set, though.

“We’ve stopped all planning, because it costs too much to keep” doing so during years of negotiations, Batt said. When the MBTA agreement is signed, “we will start that process again.”

Batt winced while discussing construction costs. Just putting the deck over the tracks will cost up to $6 million, and the university is taking over maintenance of Porter Square plaza, as well.

“It’s a pretty expensive undertaking,” she said, but one that makes sense for the school. “That’s why we never thought anyone else [would make the deal] there.”