The Path Between the Seas

by David McCullough

The lock chambers all had the same dimensions (110 by 1,000 feet) and they were built in pairs, two chambers running side by side in order to accommodate two lanes of traffic. The single flight at Gatun consisted of three such pairs. There was one pair at Pedro Miguel and two at Miraflores, making six pairs (twelve chambers) in all. The chambers in each pair shared a center wall that was sixty feet wide from bottom to top. The width of the side walls was forty-five to fifty feet at the floor level, but on the outside they were constructed as a series of steps, each step six feet high, starting from a point twenty-four feet from the base level. So at the top, the side walls were only eight feet wide. The floors of the chambers were solid concrete, anywhere from thirteen to twenty feet thick.