Two decades ago, when Karen Arpino-Shaffer’s son was a busy toddler, she had a fail-safe way to get him settled for bed: stories from her day job. In charge of more than $500 million worth of transit projects for the Massachusetts Bay Transportation Authority (MBTA), she never lacked for tales. One night, she’d tell him about a towering crane arriving to the site; the next, about building a bridge.

“When my son was little,” she recalls, “he thought you could build a bridge in a day.”

In her current job, Arpino-Shaffer, AET ’79, AEC ’00, is tasked with providing reality in the face of these kinds of fantastic expectations. She’s the Gilbane Building Company project manager on the recently greenlit effort to add four-and-a-half miles and seven new stations to the MBTA’s heavily-trafficked Green Line. At $1.1 billion, it’s the region’s most expensive construction project—she’s the only woman leading any of the top 25—and it won’t be done until 2019.

So, armed with only a PowerPoint presentation, she’ll soon be explaining to dozens of antsy town officials and community groups how projects of this scale take time.

Arpino-Shaffer welcomes the challenge: “I believe projects are always improved by the community process,” she says. And although the time line isn’t like building a bridge in a day, it’s still pretty quick—just ask any Bostonian who lived through 20 years of the Big Dig. Of course, Arpino-Shaffer knows that doesn’t make the wait any easier for the thousands of traffic-frazzled commuters eager to ditch their cars and business owners desperate for the economic boost that accompanies easy T access. “When people are passionate about a project,” she says, “it can’t happen fast enough.”

–Francis Storrs