Recent transplants to Boston could be forgiven for thinking we have but one harbor tunnel connecting downtown with East Boston. The twinned Sumner and Callahan tunnels, after all, begin and end in the same place on both sides of the harbor, a single entity for the casual observer. They were in fact built decades apart, the Sumner in 1934 and the Callahan in 1961.
With increasing volume in the Sumner, the single tunnel with traffic moving on one lane in each direction proved dangerous and inadequate, and the Turnpike Authority decided to build the Callahan. Workers toiled 24 hours a day, six days a week, crafting 14,500 tons of steel into the nearly mile-long tunnel.
In this photo from Sept. 6, 1961, the 9-foot diameter of these powerful fans used for ventilation at the East Boston end of the new tunnel dwarfed project engineer Irving R. Huie (left) and Clyde H. Galbraith, coordinating field engineer for the equipment maker. The bank of three fans could move up to a million cubic feet of air per minute.
The Lieutenant William F. Callahan Tunnel opened on Nov. 11, 1961, the 40th anniversary of the birth of the late war hero. Only son of Massachusetts Turnpike Commissioner William F. Callahan, the lieutenant fell in action April 14, 1945. His death occurred during an attack in the mountains of northern Italy, a few weeks before World War II ended.
photos, visit www.bostonglobe.com/archives.