The Fulton St. Transit Center won’t open for at least another four years, but the belowground work on the new $1.4 billion station has begun in earnest, as seen from the roof of the Corbin Building Wednesday. For straphangers, the construction on the A/C mezzanine is hard to miss, as are the service outages that have A/C trains bypassing the Broadway-Nassau stop most weekends between now and October. The M.T.A. recently finished underpinning the Corbin Building, which is adjacent to the site of the future glass-domed station at Fulton St. and Broadway. That work took about a month longer than scheduled, but the contractor will work double shifts on other parts of the project to make up the time, the Metropolitan Transportation Authority said in a report to board members this week. The new station, which will connect 12 subway lines and the World Trade Center PATH trains, is scheduled to open in 2014.
