Rosa Vasquez shifted from side to side on a broad cement overpass above a highway in Williamsburg, Brooklyn, one recent cold and bright Wednesday afternoon. She accepted a flyer for an upcoming scaffolding training session and said she would consider attending the meeting. Eight women huddled in winter jackets nearby did not look up, standing silently as Vasquez answered a stranger’s questions. Across the street, a smattering of women lingered, despondent, on the open sidewalk where they had stood since the morning. "It’s a nice idea. Why can’t women do this work?" asked the 26-year-old immigrant from Ecuador, who works cleaning houses. "It isn’t about being very strong and it doesn’t have to be very hard. You just need a good mind and hands."