A pit bull mix named Roo survived two days trapped in a dark San Francisco railway tunnel before being rescued on Tuesday. Caltrain operators eventually spotted the frightened dog hunkered down inside a Potrero Hill rail tunnel.

Train operators initially mistook Roo for a deceased animal. On the second day, a driver observed the dog move, noting its stillness led them to believe it might have been injured by a train, according to San Francisco Animal Care and Control (SFACC).

Animal control officers, alongside Caltrain staff, entered the tunnel to retrieve Roo. Officers Pone and Borg found that the dog had not been hit by a train but was simply scared and had remained in the tunnel for two days. Caltrain spokesperson Dan Lieberman described the rescue as unusual, stating that dogs typically avoid loud and intimidating train environments.

Roo had run off in a panic shortly after being adopted. The dog's microchip was instrumental in reuniting it with its owner.

SFACC, the city's animal shelter, provides care for stray, lost, abandoned, sick, injured, and surrendered animals. The organization recently rescued a goose struggling to swim at a local park, providing it with treatment at the shelter.