The MTA has restored normal subway service to the A, B, C and D trains just in time for the Tuesday morning commute. A massive water main break Monday morning had crippled the transit system in Upper Manhattan and casued flooding on the streets and subway tracks.

It stranded hundreds of thousands of people in four boroughs, while it spread water across four city blocks. A water main break in Manhattan Valley on the West Side flooded subway tracks, stopping service on four different subway train lines in four different boroughs.

The culprit was a 30-inch, 95 year-old water main. The Department of Environmental Protection says that just after 11:00 A.M. it ruptured, although, people who were on the scene when it happened described it as more than just a rupture.

"And boom!" a witness who goes by the name Cowboy told PIX11 News. "It was an explosion, definitely."

The explosion under 106th Street buckled the pavement from sidewalk to sidewalk over a large portion of the block, where it intersects with Central Park West. "It sort of looks like California looks after an earthquake," nearby resident Elizabeth Kellner told PIX11 News.

The gush of water from the broken main cascaded downhill on Central Park West. Witnesses said it left CPW looking like whitewater rapids. The deluge flowed into the grates of the subway stop at the bottom of CPW at 110th Street. MTA sources tell PIX11 News that because the subway tunnel declines in elevation from 110th to 125th Street, much of the water backed up at 125th Street, covering the subway platform there.

The water also rose in the 116th and 110th Street stations, forcing the electricity to be turned off throughout much of the subway lines that pass through those stations. The result was four of the city's twenty-four subway lines shut down.

Closed were the the D train from the Bronx, through Manhattan into Brooklyn; the C train from Washington Heights, through Brooklyn and into Queens; the B train from Harlem all the way to the Atlantic Ocean in Brighton Beach, and the A train on Manhattan's West side.

The shutdowns affected about a half million riders during Monday's rush hour. MTA crews worked around the clock pumping out water and testing the electrical systems of the affected subway lines. Street traffic had to be diverted on the Upper West Side and Manhattan Valley as well.

The DEP is responsible for the water main, but every commuter who spoke with PIX11 News blamed another set of initials for the transportation tie-up: the MTA.

"If I did my job the way the MTA does its job, I'd get fired," subway rider Allison Hickey said, as she learned that her local C train stop at 110th Street had been overcome with water.

"We spent all this money on transportation," another disappointed commuter said, "And they just let us down."

For its part, the MTA kept updating information about the situation on its website, http://www.mta.info. The DEP is handling the repair of the broken main and the investigation into its rupture.

The MTA restored full service on the A, B, C and D train lines early Tuesday.