sentences:  A permissive path runs along the left bank, passing the grade II listed Tring pumping station, Heygates flour mill, and the site of Bushell's Boat Yard.This is the only part of the canal which was built on an embankment, rather than following the contours of the land.Gamnel Bridge dates from 1797, and is a narrow hump-backed bridge, constructed of brown bricks with a red brick arch and blue brick decoration and copings.