Governor Cuomo explored an “L” of an idea Friday: Would it be possible to shorten the looming 15-month shutdown of the L train between Manhattan and Brooklyn?

With engineers he invited from Columbia and Cornell universities, the governor boarded a rail inspection car just after midnight and toured the East River tunnel damaged by flooding during Hurricane Sandy, to see if there are any alternatives to the MTA's own repair plan.

"The best way to do it, the fastest way to do it, the best way to do it, the fastest way to it -- that that has been the charge for four years," Cuomo said.

Cuomo defended stepping directly into the project just four months before the tunnel closes and service stops for the work -- a project the MTA and its own engineers have been planning and shaping for years, one that will force hundreds of thousands of L train riders to find new ways to get around.

"If there's a better way of doing it, they'll tell us there's a better way of doing it. If there's not a better way of doing it, they say that's the best that can be done, fine. Then I feel confident going to New Yorkers and saying that," Cuomo said.

But some L train riders who saw their overnight travel delayed by the governor's tunnel tour ... "It's nothing new. The MTA has been screwing up everyone's travel plans for years now," one rider said. ... questioned why he was inserting himself into the project only now.

"Governor Cuomo, you can say that you're going to inspect the tracks. We've been waiting for you to inspect the tracks for a looooong time,” one rider said.

The Governor said he's simply trying to ensure the MTA is on the right track to rebuild the tunnel and critical equipment damaged by saltwater.

"It's not that the floodwaters come in and then they disappear and everything is ok. The floodwaters came in, the salt came in, the salt stayed. And salt and electrical equipment is a toxic cocktail."

Next is a decision on whether to change the MTA’s existing shutdown plans, and if so, what the new plans should be.

Cuomo said he expects to have a full read on the trip into the tunnel in about three weeks, at which point he'll be able to determine how and if the project will change.