With two hours’ notice, a city-employed bridge tender can be summoned to the bridge operator’s house, a small brick structure, on the increasingly rare occasions when the Carroll Street Bridge needs to be opened.

“One of the things we’ve learned is that the substructure of the bridge is in worse condition than anyone understood,” said Brian Carr, assistant regional counsel at the EPA, at the January meeting. “There were repairs that were going to be needed one way or the other, and driving the piles in and all, if the bridge had been in decent condition, would have provided future stability for the bridge.”

The Carroll Street Bridge will likely remain closed long past the currently-projected March 31 cutoff as federal and city agencies work to assess and address structural issues on the span.

Last summer, engineers started work installing “pipe piles,” which would help stabilize the bridge when the federal EPA and the city begin dredging in the area. After a few months of pile driving, though, engineers realized the work was damaging the structure, and the EPA decided to reassess their plans for supporting the structure and cleaning up the 10 feet of infamous “Black Mayonnaise” beneath the Carroll Street Bridge and the Union Street bridges, Tsiamis said at a September meeting of the CAG.

From November 2020 until April 2021, workers will stabilize the Carroll Street Bridge ahead of dredging around it by sinking so-called pipe piles at the edges of the bridge bases on either side.

It is not really a restoration; city agencies are subject only to comment, not regulation, by the landmarks panel. So the Department of Transportation is leaving the 1940's handrail and demolishing the brick engine house, although it says it will reconstruct it from the salvaged bricks. But the bridge will be repainted its original color - still undetermined - and it will be nice to see it glide closed on its 100th birthday.

An existing Carroll Street Bridge was closed in 1887 and its replacement became an issue. Local property owners preferred the retractile type which slides the bridge back diagonally on rails to rest on one shore but this meant buying more land, which the City of Brooklyn was loath to do.

The unusual 1889 retractile-type bridge - the oldest in the country - has been left open since 1986, but the department has been repairing it since last December and it should be working in time for its 100th anniversary on Sept. 19.

There is an original Belgian block approach, and the bridge is wooden-planked.

The bridge is drawn in and out by cables from the engine or operator’s house on the west side of the canal and opens a 36-footwide channel in the canal.

It continues to operate today essentially as it did when it first opened.

The Carroll Street Bridge is a retractile bridge crossing the Gowanus Canal in Brooklyn. The bridge, which was opened to traffic in 1889, supports a 17 foot wide roadway and two 4.5 foot sidewalks.

As recently as the 1990s, the Carroll Street Bridge was retracted almost twice daily in order to allow passage for waterborne traffic to and from the paint factories, oil depots, sand and gravel suppliers, and warehouses lining the canal, but with the decline of industry in the area these deliveries have since become far less frequent.

We begin our tour at the Carroll Street Bridge over the Gowanus Canal. The cobblestone approach and wood planks attest to the fact that this is no ordinary bridge. In fact, it is the oldest of four retractile bridges in the United States (constructed in 1889), and it is the only wooden bridge in the city that carries cars.

The Carroll Street Bridge, constructed in 1889, spans the 36-foot-wide (11 m) channel of the Gowanus Canal and has a total length of 107 feet (33 m). The bridge uses a wooden deck to support one traffic lane and two sidewalks. The steel superstructure uses a king-post truss. In plan, the span has a trapezoidal shape, due to the angled joint between the movable span and the fixed abutment. The operating machin- ery is contained in an adjacent control house, from which wire ropes connect to the movable span. Wheels, riding on rails, are mounted underneath the movable span. The rails allow the bridge to roll away from the channel at an angle of approximately 45° from the center of the roadway.

However, this type was once common in Boston, with a dozen examples and a handful of rolling retractile bridges remaining in service in the United States, including the historically land- marked Carroll Street Bridge in Brooklyn, NY. T

A notable civil engineer, Charles O.H. Fritzche, developed the mechanical system.

Many notable names were involved in the construction of the Carroll Street Bridge. Robert van Buren, a descendant of U.S. President Martin van Buren and Chief Engineer of the Bureau of Construction, oversaw the project.

It may be inferred through historic documents that the use of a retractable bridge at this span was possibly due to the fact that an earlier design for the bridge would have required acquiring a piece of private property that the Common Council was having trouble purchasing at the time. The Landmarks Preservation Commission noted that retractable bridges are “employed to provide channel clearance in locations where other bridge types are impractical.”

It was originally powered by steam, but was converted to electric in 1907-08.

Retractable, or retractile bridges, open to allow water vessels to pass through, and the Carroll Street Bridge uses a mechanism that takes the whole span of the bridge and rolls it diagonally on wheels along steel rails using pulleys and wire cables.

The unique style of the this bridge gained it landmark status in 1987, with the Landmarks Preservation Commission citing its “rare and unusual” qualities.

As a retractile draw, the bridge opens by physically sliding out of the navigation channel on a set of three steel rails, pulled by an electrically operated pulley system. The moving portion of the bridge is a 107-foot long trapezoidal deck, supported in the middle by an iron post-and-truss frame that gives the superstructure the appearance of a suspension bridge. The operating controls for the bridge are located in a polygonal brick house on the west side of the site. The house was built during the bridge’s overhaul project of bricks salvaged from the demolition of the old operating house. One of the more interesting features of the bridge, a sign threatening a five dollar fine for anyone driving over the bridge faster than a walker’s pace, was also added during the overhaul.

The bridge was built between 1888-1889 by the New Jersey Steel & Iron Company. It replaced a wooden swing bridge that had become so rotten over the years that city engineers were forced to close it in early 1887 to everything but pedestrian traffic, fearing it would collapse under anything heavier.

Construction of the new one was begun at the end of the year. It opened in September the following year, completed at a cost of $29,600.

The Department of Transportation closed the bridge in 1985 after an inspection revealed multiple holes in the road deck, seriously corroded steel, and a broken operating mechanism. After a $1.5 million overhaul by city workers, the bridge was able to reopen to traffic just in time for the 100th anniversary of its initial opening in 1989.

The Carroll Street Bridge is a retractile drawbridge that crosses the Gowanus Canal in the borough of Brooklyn. It is notable as the oldest surviving retractile bridge in the United States, with only three others still in existence: two non-operational draws in Boston, and one carrying Borden Avenue over Dutch Kills in the borough of Queens.