This traditional commuter rail line runs along the Peninsula into Silicon Valley [1], from San Francisco [2] to San Jose [3] with limited continuing service to Gilroy. CalTrain (www.caltrain.com [4], fares vary $2.25–11/one-way) “Baby Bullet” trains can get you from San Jose to San Francisco in under an hour during commuter hours.
Extra trains are often added for San Francisco Giants [5], San Francisco 49ers [5], and San Jose Sharks [6] games.
You must purchase a ticket in advance at the vending machines in all stations, or get your 10-ride card stamped before you board a train. The San Francisco [2] main CalTrain station sits at the corner of 4th Street and King Street, within walking distance of AT&T Park [7] and Moscone Center.
Links:
[1] http://www.moon.com/destinations/california/san-francisco-and-the-bay-area/silicon-valley
[2] http://www.moon.com/destinations/california/san-francisco-and-the-bay-area
[3] http://www.moon.com/destinations/california/san-francisco-and-the-bay-area/silicon-valley/san-jose
[4] http://www.caltrain.com
[5] http://www.moon.com/destinations/california/san-francisco-and-the-bay-area/recreation/spectator-sports
[6] http://www.moon.com/destinations/california/san-francisco-and-the-bay-area/silicon-valley/san-jose/sports-and-recreation
[7] http://www.moon.com/destinations/california/san-francisco-and-the-bay-area/sights/financial-district-and-soma/att-park