The San Francisco and North Pacific Railroad, incorporated as the Northwestern Pacific Railroad in 1907, established its southernmost terminal in Tiburon in 1884. To improve freight handling, the company built the ferryboat Ukiah, launched in May 1890, with rail tracks for standard and narrow gauge rail cars, but the vessel required a special slip for loading. In 1890, a slip was built in Tiburon with tracks on an apron that could be raised and lowered to match the tide level. Two very large wheels and six smaller wheels carried cables that supported the apron. The wheels were first enclosed within two towers, but as the slip was updated and moved over the years, they were left exposed in an open framework called a gallows frame. When the slip was removed in 1974, the Southern Pacific Development Company donated the wheels to the Town of Tiburon as artifacts, and they show the size and mass of components that once stood about thirty feet above the tracks in operation.