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.
Panamax
On October 22, 2006, the Panama Canal Authority (with the support of the Electoral Tribunal) held a referendum for Panamanian citizens to vote on the Panama Canal expansion project. The expansion was approved by a wide margin, with support from about 78% of the electorate. Construction began in 2007, and after several delays, the new locks opened for commercial traffic on 26 June 2016.
The plans to build another set of larger locks led to the creation of the Neopanamax or New Panamax ship classification, based on the new locks' dimensions of in length, in beam, and in depth. Naval architects and civil engineers began taking into account these dimensions for container ships. With the new locks, the Panama Canal is able to handle vessels with overall length of 366 m (1201 feet), 49 meters beam and 15.2 meters draft. and cargo capacity up to ; previously, it could only handle vessels up to about . The Neopanamax standard accommodates ships up to 120,000 DWT.