Panama Canal Railway
The Panama Railway also operated a significant shipping line, connecting its service with New York and San Francisco. It ran a Central American line of steamships linking Nicaragua, Costa Rica, San Salvador, and Guatemala to Panama City. The shipping service was greatly expanded when canal construction began. Ships included the SS "Salvador", SS "Guatemala", SS "Cristobel", and , which became the first of the ships to cross the completed canal in 1914.
In 1904 the United States took over the license to build and operate the canal. The choice to use locks and an artificial lake (Gatun) meant that the old railway route from 1855 had to be changed because it followed the Chagres River valley, which would be flooded by the lake. Also, the railway would be extended and altered continuously for the building process. The stock of the Panama Railway Company, vital in canal construction, was entirely controlled by the United States Secretary of War.
Panama Canal locks
The Panama Canal locks () are a lock system that lifts a ship up to the main elevation of the Panama Canal and down again. The original canal had a total of six steps (three up, three down) for a ship's passage. The total length of the lock structures, including the approach walls, is over . The locks were one of the greatest engineering works ever to be undertaken when they opened in 1914. No other concrete construction of comparable size was undertaken until the Hoover Dam, in the 1930s.