Repairs to a Storm-Damaged Tunnel Will Disrupt R Line Service for a Year Extensive repair work on a subway tunnel connecting Brooklyn and Manhattan is scheduled to start this weekend, making many R train riders adjust their commutes for more than a year. The Montague tube under the East River was one of nine underwater tunnels that were severely damaged during Hurricane Sandy. While workers were able to get the line running through the tunnel two months after the storm, it was clear that the damage would require a more extensive repair effort, according to the Metropolitan Transportation Authority. After the storm, 27 million gallons of water were pumped out of the tube, said Kevin Ortiz, a spokesman for the authority. But the damage was lasting. "Salt water and metal do not mix," Mr. Ortiz said. The repairs, which include work on the tracks, lighting, pump rooms, circuit-breaker housing, signals and power cables, are expected to cost $308 million. The tunnel is not scheduled to reopen until October 2014. While the tunnel is closed, the R train will run in two sections on weekdays. Service between Queens and Manhattan will function normally. In Brooklyn, the train will continue to make all stops between Bay Ridge-95 Street and Court Street. On weekends, the R train will cross the Manhattan Bridge, and late at night the N train will replace the R running over the bridge. Mr. Ortiz referred riders to the transportation authority's Web site for a full discussion of the effects of the tunnel's closing and the variety of alternative commuting options that are available. As a historical footnote, the authority said, the last train to travel through the tunnel before the closing was scheduled to leave the Court Street station on Friday about 11 p.m.