lines, two light rail systems, two ferry systems, Amtrak inter-city rail services, and four major overlapping bus agencies, in addition to dozens of smaller ones. Most agencies accept the Clipper Card, a reloadable universal electronic payment card. An extensive rail infrastructure that provides a mix of services exists within the nine Bay Area counties. Bay Area Rapid Transit, commonly known as BART, provides rapid transit service between San Francisco and Contra Costa, Alameda, San Mateo, and Santa Clara counties. Caltrain, which runs on the right-of-way of the historic Southern Pacific Railroad, provides commuter rail service on the San Francisco Peninsula, linking the cities of San Francisco, San Jose, Gilroy, and numerous peninsula cities in between. The Millbrae Intermodal Terminal provides transfers between Caltrain and BART. The Altamont Corridor Express, commonly known as ACE, also provides commuter rail service, but from the Central Valley into Silicon Valley, terminating at San Jose’s Diridon Station. To the north, Sonoma–Marin Area Rail Transit (SMART) line provides commuter rail service in Sonoma and Marin counties. In addition, Amtrak has a presence throughout the Bay Area. There are two intercity services, the Capitol Corridor connects Bay Area cities to Sacramento and the San Joaquins connects to cities across the San Joaquin Valley. Additionally, there are two long-distance services, the Coast Starlight offers service to Seattle and Los Angeles, while California Zephyr runs to Chicago via Denver. The Bay Area also has two light rail systems: one run by San Francisco Municipal Railway called Muni Metro, which operates within the city of San Francisco, and the other run by the Santa Clara Valley Transportation Authority, which operates within Santa Clara County. A series of overlapping bus agencies provide additional public transit coverage to Bay Area regions both served and not served by rail transit. The four largest agencies, Muni, AC Transit, SamTrans, and VTA operate within the City of San Francisco, East Bay, the Peninsula, and South Bay respectively, although their service areas generally overlap with neighboring agencies and numerous smaller agencies. All of these agencies also provide limited night bus service, which are intended to "shadow" the rail routes that are closed during the nighttime hours for maintenance. In addition, the four bus agencies are each independently pursuing constructing bus rapid transit systems by developing separated right-of-ways and traffic signaling on busy corridors, including on Geary and Van Ness for Muni, El Camino Real for SamTrans