The Second Avenue subway, finally under construction on the Upper East Side of Manhattan, is of course a vast underground project. The $4.45 billion first phase, now scheduled to be completed in 2018, will extend from 96th Street to 63rd Street and Lexington Avenue.
But the project will also include construction above ground -- not just station entrances but also a half-dozen boxy buildings on corners along Second Avenue that the transit agency acquired through condemnation. These so-called ancillary buildings, ranging in height from five to eight stories, will house ventilation equipment. They are also intended to disperse smoke and allow for evacuation from subway tunnels in the event of an emergency.

