Here the ropes pulled in from the rowboat are exchanged for heavy cable and attached to the electric locomotives pictured on the right.

Four engines (called mules) are assigned to the bow (two on each side) and two attach aft. The mules do not actually pull the ship through the canal -- it proceeds on its own power -- but rather steady it as we move forward and water flows into the lock chamber.

The mules are so named because of the kind of work they are doing. No actual mules were ever used for this task; they have always been electric.