By Dan Rivoli , Jillian Jorgensen and Larry Mcshane

The L-pocalypse is officially cancelled.

Gov. Cuomo, in a stunning Thursday announcement, told 225,000 happy commuters that the planned April closure of all L train service between Manhattan and Brooklyn was off.

The mass transit respite comes courtesy of an engineering team that conjured an unprecedented plan to repair the water-damaged tunnel beneath the East River without shutting down service.

"I have confidence in saying to the people of New York (that) this is the shortest, best route to repairing the tunnel," the governor declared at a Manhattan news conference.

The planned 15-month shuttering of the line will instead be replaced by nothing worse than night and weekend closures in its two century-old tubes, allowing service to continue despite the repair work, according to the governor.

The lengthy closing of the Canarsie Tunnel was originally set to begin April 27, with service on the L train limited to Brooklyn only.

A panel of engineering experts from Columbia and Cornell universities "proposed a new design to use in the tunnel" -- one never before tried in the United States, Cuomo said.

"It's highly innovative but feasible," said Cuomo. "With this design, it would not be necessary to close the L train tunnel at all, which would be a phenomenal benefit to the people of New York City."

Officials said the new and improved method will still take between 15 and 20 months to complete -- but without wreaking havoc on the lives of 225,000 straphangers who use the L or the businesses along the line.

Acting Metropolitan Transportation Authority chairman Fernando Ferrer said the agency was on board with the unprecedented approach to subway tunnel repair.

"No L-pocalypse," said Ferrer, referring to the nickname for the shutdown. "This is a less invasive, more efficient approach...and it represents a huge win for our system and our customers."

The change in approach to repairing the damaged tunnel contradicts a June 2018 MTA report citing "consulting engineers" with New York City Transit who "concluded that completing the required work solely on nights and weekends was infeasible."

The new repair job will be scaled down compared to the MTA's original plan to demolish and rebuild parts of the tunnel. The sensitive cables housed in duct banks inside the tunnel bench wall will now be "racked" high on one side of the tunnel, officials said.

The governor toured the tunnel just last month, releasing a statement that the state had "some of the best minds in the world" studying the situation.

Mayor de Blasio announced his support for the new approach: "Anything that avoids disruption I favor, obviously."

But the mayor hedged his bets a bit after Cuomo's announcement came out of left field.

"One, I want to reserve judgment until I've got a thorough briefing on the plan," said de Blasio. "Two, whatever the plan is, we have to confirm that it's going to work in terms of the reality we've been facing.

The Canarsie Tunnel, as the MTA calls the tube connecting the boroughs, was flooded with corrosive salt water when Hurricane Sandy pounded the city in 2012.

"What these people have designed is the first of its kind in the United States of America," said Cuomo. "No rail system has used this approach before...This is really a unique design, a unique system."

The closure would have halted all service between Bedford Ave. in Williamsburg and Eighth Ave. in Manhattan. Instead, one of the two tubes will stay open during the night and weekend repair work so trains can still pass by in both directions

Mary Boyce, dean of the school of engineering and applied science at Columbia University, said the solution came from three weeks of collaboration with the MTA and other consultants.

(c)2019 New York Daily News