Retractile bridge

Carroll St. Bridge over the Gowanus Canal, Brooklyn. When the bridge opens for vessels on the canal, it slides sideways into the pocket at left.

Retractile bridge : a type of movable bridge slides sideways to clear the way for water traffic

Most moveable bridges – drawbridges – shift upwards to make room for passing ships. Retractile bridges are an unusual design that, instead, moves out of the way to the side.

The Carroll St. Bridge, spanning the narrow Gowanus Canal in Brooklyn, N.Y., is one of only four retractile bridges in the U.S. It dates to 1889, when Brooklyn was still an independent city.

A winch, housed in the brick bridgetender’s shack, pulls the bridge along a set of rails, clearing the canal for boats. With the departure of industry from the Gowanus, the bridge only opens a few times a month.

The bridge only recently returned to service, following repairs of damage caused by Hurricane Sandy.

The approaches to the tiny bridge are lined with cobblestones, lending to the air of quaintness. Cities kept stone pavers in industrial areas because they better resist the wear of heavy trucks.