A southbound Caltrain emerges from a tunnel in San Francisco, California, on Jan. 13, 2017. A southbound Caltrain emerges from a tunnel in San Francisco, California, on Jan. 13, 2017. San Francisco Animal Care and Control officers lead Roo out of a Caltrain tunnel near 16th and Mississippi streets, where he had spent close to two days. A runaway dog is back home safe after spending two days in a San Francisco Caltrain tunnel. “Not many people think to look in the Caltrain tunnel for their dog,” Campbell said.