Service on the 1, 2 and 3 lines resumed shortly before 4 p.m., almost 11 hours after the trouble began.
The 36-inch main, installed in 1922, broke near Broadway and West 62nd Street around 5 a.m., with the water spreading for blocks. It was several inches deep in places and flooded the 66th Street subway station.
The FDNY says they started receiving calls for what they thought was a leaking fire hydrant, but responders quickly realized it was something much more serious.
DEP Commissioner Vincent Sapienza reported that it took a long time to find the right valve, which was finally shut off to stop the leak around 8 a.m.
"One of the issues was the water on the street, the valves are in manholes," he said. "Finding those manholes was a little bit challenging. Being a large water main as well, there are multiple valves that are involved in getting it shut off. That's why it took that time."
He speculated that the recent fluctuation in temperatures could be to blame, although a cause for the break has not yet been determined.
Cars were seen with water up to their doors at a nearby parking garage on 62nd Street. It is estimated that more than 50 cars were destroyed.
Steam was also spotted pouring out of the street in a huge plume on 62nd Street.
The FDNY reported that three buildings sustained significant flooding in their basements, and they had firefighters with pumps at the various scenes to remove the water.
Officials give an update on the UWS water main break:
Broadway southbound will be closed in the area of the water main break for at least a few days, although the northbound side of the avenue will remain open, as will the sidewalk.
Some parts of Columbus Avenue and surrounding side streets may be closed periodically for repairs.
Subway operators started calling in water rushing into the 1, 2, and 3 lines.
Executive Vice President and Chief Operating Officer-Subways Frank Jezycki said water was rushing in through the emergency exit hatchway, cable ductwork and manholes of the 66th Street station, reaching the third rail.
The MTA says 500,000 gallons of water made it into the subway system at height of the incident, and crews spent the morning pumping the water off the tracks.
Commuters were forced to take the A, B, C, and D lines to get to their destinations, and straphangers reported incredible crowding conditions..
"It was heavier than normal on the A, B, C, D lines, but nothing we can't handle," Jezycki said.
As the tide receded, workers could be seen later Monday night digging a huge hole to replace the water main.
Check mta.info for the latest information on delays and service changes.
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