The San Francisco and San Jose Railroad (SF&SJ) was a railroad which linked the communities of San Francisco and San Jose, California, running the length of the San Francisco Peninsula. The company incorporated in 1860 and was one of the first railroads to employ Chinese laborers in its construction. It opened the first portion of its route in 1863, completing the entire 49.5-mile (80 km) route in 1864. The company was consolidated with the Southern Pacific Railroad in 1870. Today, Caltrain and the Union Pacific Railroad continue to operate trains over part of the company's original route.

Caltrain is a California commuter rail line serving the San Francisco Peninsula and Santa Clara Valley. The southern terminus is in San Jose at Tamien station with weekday rush hour service running as far as Gilroy. The northern terminus of the line is in San Francisco at 4th and King Street. Caltrain has 28 regular stops, one limited-service weekday-only stop, one weekend-only stop (Broadway), and one football-only stop (Stanford). While average weekday ridership in 2019 exceeded 63,000, impacts of the COVID-19 pandemic have been significant: in August 2022, Caltrain had an average weekday ridership of 18,600 passengers.