R train service between Manhattan, Brooklyn to be restored by Friday morning

R train service between Manhattan and Brooklyn is set to be restored by Friday morning, the MTA said.

The Montague Tunnel, which the train traverses between boroughs, has been closed since millions of gallons of water flooded it during superstorm Sandy.

"The return of the full length R route is an enormous achievement that will take some of the pressure off of the 65,000 commuters who use this line every day," Gov. Andrew M. Cuomo said Thursday.

The tunnel was knocked out of service after its tracks, signals and electrical components were flooded with saltwater, damaging the equipment, the MTA said.

Only two sections of the subway system remain down: the A train between Howard Beach and the Rockaways, and the 1 train south of the Rector Street in lower Manhattan.