The United States took over on May 4, 1904. Under the leadership of John F. Stevens, and later George Washington Goethals, the American effort started work on a cut that was wider but not as deep, as part of a new plan for an elevated lock-based canal, with a bottom width of ; this would require creation of a valley up to wide at the top. A vast amount of new earthmoving equipment was imported, and a comprehensive system of railways was constructed for the removal of the immense amounts of earthen and rocky .