The MTA took extensive measures before the storm to limit the amount of water flooding into tunnels, including by boarding up ventilation grates in low-lying stations, piling sandbags at station entrances, inflating a rubber dam in the Long Island Rail Road's West Side yards in Manhattan and hastily erecting a floodwall across the mouth of the No. 3 train tunnel near East 148th Street in Harlem.

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The same team assessed the entire museum (150, 000 square meters of lighting, heating, electrical and ventilation systems) and came up with a seven-year plan detailing when the equipment would have to be replaced and how much it would cost annually.

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It travels through air vents and cracks in walls, along ventilation and elevator shafts, and up stairways.

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