The tunnel fans were powered by large McIntosh and Seymour 4-cylinder oil engines of an early design. The engines weighed 156,000 pounds and were over 20 feet long and 14 feet high. They operated at a speed of 190 rpm and burned Bunker C fuel oil. They may have been "hot bulb" engines which were an early type of industrial engine similar to a diesel. This type of engine needs preheated fuel and this is where a steam plant would have been used and may be the reason for the steam power legend. The fans were 12 feet 3 inches in diameter and 8 feet 3 inches wide. They were capable of delivering 700,000 cubic feet of air per minute. (Thumbnail photo number five shows a tank car on the building's siding which probably delivered the Bunker C fuel oil.) - Sep 1917 Canadian Railway and Marine World.