The Williamsburg Bridge is a suspension bridge in New York City over the East River, connecting Brooklyn’s Williamsburg area to the Lower East Side in Manhattan at Delancey Street, and was the second one built across the East River. Built in 1903, it was the longest suspension bridge in the world at the time at over 1000 feet long (a title previously held by the Brooklyn Bridge). Today it is one of the busiest carrying vehicles between the city’s two boroughs. Previously, we brought you 10 fun facts about the creation of the bridge, but there’s plenty of interesting history surrounding the structure upon its completion. So, we’ve compiled a list of the top 10 secrets of the Williamsburg Bridge.

10. Elevated Trains Didn’t Run On It Until 1908

The Williamsburg Bridge opened on December 19, 1903 to pedestrians, bicycles, and horse-drawn carriages. The New York City subway system did not open until October 27, 1904, almost one year later. But that still leaves four years of no trains running service across the bridge. This was due to the surrounding complications between the Greater New York Area and the privately owned railway companies. The bridge originally designated the inside lanes for street cars and the outside lanes for buggies. But once street cars became obsolete, the inside lanes were converted for automobile traffic.

As the increase in automobile usage increased, the bridge had to be adjusted with the increase in traffic, which ultimately led to the 8-lane expansion in the 1920s. The trolley’s, or elevated city rail lines, were then able to run across the river. The original rapid transit tracks in the center of the bridge were used by the Brooklyn Rapid Transit Company elevated rail, but today, the J/M/Z subways use the bridge.

A notable remnant of the Williamsburg trolley remains at the Essex/Delancey street stop today, which the Lowline hopes to turn into the world’s first underground park. Service from Brooklyn to Manhattan back then stopped through the Williamsburg Bridge Rail Terminal at Essex and Delancey.

Next, check out the Trolley Ghosts of the Abandoned Essex/Delancey Williamsburg Bridge Rail Terminal in NYC.