Grand Sluice and Railway bridge over the River Witham at Boston, Linconshire aerial photograph

aerial photograph of the Grand Sluice and Railway bridge over the River Witham at Boston, Lincolnshire England UK. The Grand Sluice was built in 1766 and extended in 1881. It separates the tidal and non tidal portions of the river. The Grand Sluice Railway Bridge was built in 1885 to a design by Richard Johnson. These days only one of the two tracks is used.