A giant tortoise brought trains to a halt when it was found on a railway track.
The injured animal was spotted near Harling Road, north east of Thetford, Norfolk, on the Cambridge-bound line at about 12:40 BST.
Greater Anglia said three services were affected by the tortoise's presence.
Swallow Aquatics in East Harling said the tortoise, Clyde, had gone missing on Sunday and had now been taken to a vets, as it was hit by a train.
The pet shop said the 2.5ft (76cm) long tortoise had a hole in its shell after the collision.
Diane Akers, a passenger on the 11:22 train from Ely to Norwich, photographed the tortoise on the opposite track when her train came to a halt.
"It was very large and filled a substantial area of the track," she said.
"I tried to tweet Greater Anglia, but I'm not sure the message got through.
"When we got to Norwich station I told staff in the office there, and the chap looked at me as if I was mad – and then a police officer came along and said he'd seen my tweet."
BBC reporter Nic Rigby was a passenger on another train, from Cambridge to Norwich, that ground to a halt.
"The train's been delayed due a giant African tortoise on the line," he said.
"The train inspector announced that he's having trouble believing it – but it's true."
A Greater Anglia spokeswoman said: "We are sorry for the disruption caused to customers between Norwich and Cambridge this afternoon.
"This was due to a very large, injured tortoise on the line near Harling Road.
"Network Rail attended and helped the animal. Services were able to run from 13.25."
She said two trains were terminated early and one service started 20 minutes late.
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