In the foreground, you can see the electric tug with its crew aboard. In this photo, the tug is only pulling two small barges but was very capable of tugging many more on the journey through the 3.33-kilometre tunnel.
The electric tug replaced an older steam-powered and coke fired tug which was a disaster in the tunnel. Plumes of smoke were unbearable for all crew. The "modern" hydro-electric powered version was a state of the art piece of engineering. At both extremities of the canal summit, a water turbine was built. Using sluice gates to send water onto the blades which then rotated and generated the 600 volts of energy which was directed into the overhead cable. The tug simply hooked onto this cable, drew the electricity into its electric motor which turned a cogged wheel that pulled on a 7-kilometre iron chain that lay on the canal bed.