Source: Historical Society of South San Francisco

South San Francisco, CA
Departing Leipsic Junction
c. 1941

The San Mateo Interurban line opened in the early 1900s as an electric streetcar route and
served commuters riding from San Mateo County to San Francisco, and vice versa. In many ways
the route, also known as the “40 San Mateo,” is the ancestor of today’s Daly City
and SFO portion of the BART system combined with the Caltrain line. Starting
in 1903, this “interurban” line traveled from downtown SF via Mission Street all the way out
to Daly City, then eventually reaching the cemeteries in Colma, following Mission Street the
entire way. Past Colma, similar to BART, the 40 San Mateo turned southwards towards
San Bruno where it began to run parallel to Southern Pacific’s heavy rail line—today’s
Caltrain route.

After San Bruno, the 40 San Mateo continued south with stops in Millbrae, Burlingame,
Hillsborough and then San Mateo, all stops that are familiar to Caltrain riders. Some
of the station buildings that stand on the Caltrain line today were also used by the
40 San Mateo, most notably the historic Burlingame Station. There were many other stations
along the route that no longer exist, including stops at each of the different cemeteries,
as well as other forgotten names like Leipsic Junction, South Lomita and Baden Kennel Club.

This 20 mile long route began operation under United Railroads in 1903, then became part of
Market Street Railway in 1921, and was eventually incorporated into Muni in 1944. After
several cutbacks in service, Muni ceased to operate the line in January of 1949, much to the
dismay of many of the line’s riders on the peninsula.

~Courtesy #SFMTA