The plan to plunk a 677-foot, 49-story tower atop South Station, along with two other squatter buildings, appears to be moving forward. Houston-based developer Hines has a new financial backer and has been meeting with city as well as state officials about the project, which dates way back to 1991 and which once included a 759-foot tower in its proposal.

Part of the movement on the 677-foot plan is that Hines' development rights for the site expire in April 2017. Coincidentally (we imagine), the firm's website clearly says it plans to start construction above South Station early next year.

The main tower would instantly become one of the 10 tallest in Boston—in New England, really—and would join a forest of newer spires, including One Dalton, Millennium Tower, and the big-time addition to the Copley Place mall.

There are many variables re: Hines' plans, not least of which what will go into the tower itself. The most recent plans have office space occupying most of it, but Hines is apparently tweaking that to include more housing. (The smaller two buildings would hold a hotel and condos under current plans.) There's also the question of how the massive project would fit in with the transit hub's own expansion, including new tracks.

Stay tuned. Public meetings and government decisions to come.