sewer-machine

from The Century Dictionary.

• noun A special form of excavator of the chain-bucket dredge type used to cut the ditch or trench for sewers or other underground conduits by mechanical means and do away with hand-labor and improve the speed of such Work.
• noun A name loss correctly given to the combination of wire-rope tramway with hoisting capacity, used in making sewer trenches, or similar excavations for subways or pipe-lines.