I wasn't aware either, but your guess appears to be correct: "Between 1848 and the completion of the transcontinental railroad in 1869, the principal mode of tr

I wasn't aware either, but your guess appears to be correct: "Between 1848 and the completion of the transcontinental railroad in 1869, the principal mode of transportation between California and the east coast of the United States was to travel by steamer from San Francisco to the west coast of Panama, cross the isthmus by train, and take a steamship to New York." http://www.columbia.edu/~dj114/SS_Central_America.pdf http://www.columbia.edu/~dj114/SS_Central_America.pdf