While not specifically a real-time tracker, this neat website has a clickable map where you can locate transit vehicles, get next stop information (though not time), and a map of the route. It seems more likely a visualization of where things should be if the schedules are followed instead of something to assist passengers. From what I’ve found, it covers the Los Angeles and San Francisco regions in California. Other cities, such as Phoenix, Arizona, are also covered. The site is Swiss, hence the .ch TLD.
