A two-year-old tabby cat was found in "surprisingly good condition" after travelling 1,700 miles trapped in a train's undercarriage.
Polly, whose owner is a retired train driver, did though need her front left leg amputating after it became infected.
Her trip took in London, Swansea, Wiltshire and Cornwall, before train manager Emily Mahoney-Smith, 33, heard her desperate moans.
Ms Mahony-Smith told The Times: "It's amazing she survived for so long. I think she climbed into the train as she was chasing rats in the shunting yard.
"She was in surprisingly good condition, although she was incredibly smelly from her infected leg."
Polly is now recovering and will soon return to the Plymouth home of her owners, 84-year-old Arthur Westington and his wife Louisa, 82, who say they “can’t wait” to have her home.
It is thought she crawled into the train at a rail yard in Plymouth while a maintenance panel was removed last Thursday.
Polly then spent the next two days trapped without food or water.
A spokesman for First Great Western, the train operator, said: "We're pretty sure the cat had been stuck on board for some time. It was ensconced in the underbelly and couldn't have got there unless the train was in a depot.
"That part of the train isn't accessible from a normal station stop so the latest it could realistically have stowed away would have been at Plymouth, where it started service. We've calculated it did at least 1,667 miles."
Ms Mahoney-Smith heard Polly's cries at Plymouth but could not find where they were coming from until the train reached St Germans, where she and the driver got out to investigate.
They found Polly, put her in a box and gave her the tuna from a buffet sandwich.
On-call vet Matthew Berriman, having been called by the RSPCA, discovered Polly was microchipped.
Despite her injuries she was operated on and Mrs Westington was contacted.