What did the United States build in Panama before the Canal?

In 1850 the United States began construction of the Panama Railroad (now called the Panama Railway) to cross the isthmus; it opened in 1855. This overland link became a vital piece of Western Hemisphere infrastructure, greatly facilitating trade. The later canal route was constructed parallel to it, as it had helped clear dense forests.

Explanation:

because mexico wanted to choose a centralized location

answer placeholder because the system is messed up