Part of the N subway line in Brooklyn will be shutting down for a year as the MTA makes repairs to an underground tunnel.

Starting in May 2018, the express N tunnel between 36th and 59th Streets in Sunset Park will be closed.

The N will share a track with the R local train during this time.

The MTA says the express tunnel has been damaged by rainwater and needs new columns, concrete walls and steel.

The agency says the N train will run normally until then and straphangers are not in any danger while the tunnel remains open.