Malbone Street Wreck
On November 1st, 1918, at 6:22pm, the peak of rush hour, a packed Brooklyn Rapid Transit train jumped the tracks on a tight curve, killing 93 people. It remains one of the worst train wrecks in US history.
Here's a current map showing the wreck site (red arrow):
Just to the upper right of that intersection is the old site of Ebbets Field, home of the Brooklyn Dodgers. It's now a housing development.