Construction is moving ahead on one of the summer’s blockbuster livable streets projects, the addition of new pedestrian and bicycle amenities at Grand Army Plaza. As often happens in Brooklyn, in the course of digging up the pavement the crew unearthed some remains from the previous incarnation of the street. Susan Kille posted this shot of old trolley tracks on Union Street, which were briefly exposed over the weekend.

Trolleys running on Union, Grand Army Plaza, and Prospect Park West were part of the surface rail network blanketing Brooklyn and much of Queens before streetcars exited the scene in the 1950s.

Doug at Brooklyn Spoke has a great series of shots from the era when trolleys plied PPW, there was nary a parked car in sight, and the sidewalks were more generous than they are today. It’s a fitting response to opponents of the Prospect Park West redesign who seem to think that preserving the street’s historic charm entails keeping the parking lanes exactly as they were in May, 2010.