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
An enlargement scheme similar to the 1939 Third Lock Scheme, to allow for a greater number of transits and the ability to handle larger ships, had been under consideration for some time, was approved by the government of Panama, The cost was estimated at , and the expansion allowed to double the canal's capacity, allowing more traffic and the passage of longer and wider Post-Panamax ships. The proposal to expand the canal was approved in a national referendum by about 80 percent on October 22, 2006. The canal expansion was built between 2007 and 2016, though completion was originally expected by the end of 2014.