In 1873, construction began on a railroad from Sausalito to Corte Madera. The tracks crossed Richardson Bay to Strawberry Point on a trestle. The roadbed wound its way up to the crest of Corte Madera Ridge and Alto Pass and then down to Corte Madera. Passenger service began in July 1875. In 1884, a tunnel was bored through Corte Madera Hill, and the route from Sausalito was changed to follow what is now the Mill Valley Sausalito Multi Use Path. A new railroad station at the present Ashford Ave. and Lomita Drive was called “Blithedale” because carriages from the Blithedale Hotel met trains there. A timetable in 1889 names the station ”Alto (Blithedale)”. An unincorporated community and a school nearby are named Alto. The tunnel is officially the Alto Tunnel.
In 1890, a branch line of the North Pacific Railroad was installed. It ran from the main line to a depot in the new real estate development that would become the town of Mill Valley. The name of the stop where the branch line began was “Bay Junction”, but it was soon changed to “Mill Valley Junction”. In 1912 the name of the junction was again changed to “Almonte” (to the mountain).