In the design of the main tunnel, ingenious provision was made for recession of the Falls. From the opening in the cliff for three hundred feet the lining will be put in in rings six feet long; this arrangement will allow a joint to drop out whenever the Falls recede so that it is exposed, thus leaving a smooth section always at the end of the tunnel. Through this main tunnel and through the branch races, the water, after having left the turbines, will whirl along at the rate of twenty-six feet per second, having generated a total of 125,000 electric horse-power. In engineering problems connected with the tunnel and the construction of the plant, the work of this company far surpasses that of any of the others. In order to secure a place for the wheel-pit and gathering dam, an area of about twelve acres in the bed of the river was converted into dry land. To do this a coffer dam was constructed 2153 feet in length and from twenty feet to forty-six feet wide in water varying in depth from seven feet to twenty-four feet, besides being very swift in most places. About two thousand feet above the Falls, in the space thus deprived of its water, an immense wheel-pit was sunk into the solid rock. On the bottom of this pit, 150 feet below the surface rest the monster turbines, from which two tail-races conduct the water to the main tunnel. A large gathering dam sufficient to supply the maximum capacity of this plant runs obliquely across the river for a distance of 750 feet. The height of this dam varies from ten to twenty-three feet; it is constructed of concrete, the top being protected by a course of cut granite. The power plant is located on the original shore line and parallel to it in Queen Victoria Park. In the power room are to be found eleven monster generators capable of developing 12,500 horse-power each.