Eight feet. That's how far Manhattan Bridge swings from one extreme to the other when a subway train crosses. The train tracks are on the outside of the bridge, with a lower roadway between them and an upper roadway above them on each side. "They placed the subway tracks on the outside instead of in the center as they did on the Williamsburg," Tom Nilsson, project manager for Koch Skanska, told ROADS & BRIDGES. "It's fine when you have subway trains on both sides," but when there is a train on just one side, the swing puts tremendous stress on certain parts of the bridge. "What's being done right now is that we basically are replacing all the bad parts," said Nilsson. "In addition, we are stiffening the bridge to minimize this movement."
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