A horse tethered at night to a concrete post on railway property took fright at a fast train, broke its halter, and bolted into a tunnel. Four days later, o coal-merchant, presuming his horse to have been stolen, informed the police, and took to carrying coal in a furniture-van. The same evening, a late-shift driver of an electric-train spoke of seeing a large animal silhouetted against signal lights on the underground track between Baker Street and St.John's Wood. The following day a track- inspector found the prints of a horse in a sand-pit at Tower Hill. Trampled flower-beds at Baron's Court and horse manure found in the tunnel at Green park persuaded railway officials to caution their drivers, although no authority believed an animal could survive the electrified rails.
Several further sightings of a horse by rail employees and one sighting of a cow by passengers prompted the rail-board into closing the entire railway system for twelve hours to search the tunnels thoroughly. They found a dead pig, a colony of bats and a family living in a signal box under Highgate Hill, but no horse.
Four years later, seven people were killed and twenty- nine injured when a posse of black horses stampeded out of the tunnel at Gloucester Road and chased early morning travelers into the path of an oncoming train.