The building of the actual [I 008 / locks] themselves began in 1909 and was only completed four years later. Built in pairs to cope with two lanes of traffic, they were the biggest engineering structures in the world at that time. The chambers were made from wooden frames filled with concrete and were connected by enormous passageways where the water ran through. Through 70 holes, water from Miraflores and Gatun Lakes filled and emptied the chambers, [V 008 / gently lifting and lowering the vessels] that passed through the canal. Equally large [L3 303 / steel sliding gates] controlled the flow of water in and out of the chamber which ran on roller bearings and were also raised and lowered accordingly. The water moved from one chamber to another through the force of gravity. When the level was correct for ships to pass through, a rising stem-gate valve shut off the flow of water, and the gates then opened. This entire operation of the canal was engineered to be [L3 304 / overseen by one man] on a single set of controls.
