with the growth of population in the late nineteenth century, and the proliferation of water closets, the rivers around manchester were becoming grossly polluted, and the city of manchester decided to build two deep level sewers to intercept existing sewers. when the first one reached davyhulme, further extension was blocked by the manchester ship canal, and so a treatment works was built there. the works used precipitation tanks, and a gauge tramway was built, to facilitate the movement of materials around the site. the first steam locomotive was acquired in 1897, and a further fourteen steam and two diesel locomotives operated on the system before its closure in 1958.