The unusual obstacle was first spotted by traveller Diane Akers who saw the animal had been injured by a passing train.
The 50kg reptile had suffered damage to the top of his shell but was still alive, so she rushed to find the nearest rail worker to report the animal.
"The chap looked at me as if I was mad," Akers told the BBC. "Then a police officer came along and said he'd seen my tweet."
Passengers on the busy line of rail linking Cambridgeshire and London Stansted could hardly believe the excuses.
Network Rail stopped trains for over an hour through Harling Road station so that Clyde could be safely rescued. He was taken for treatment by a nearby vet surgery.
A patch of shell roughly 10cm across had been knocked off his back but no vital organs were injured and he was expected to heal fully in time.
A bigger challenge was finding where the 50kg tortoise had escaped from. There aren't many zoos - or giant tortoises for that matter - in that part of Cambridgeshire.
Rail workers traced the tortoise back to Swallow Aquatics which kept large reptiles.
"One of our team who rescued Clyde was aware of a nearby centre who owned giant tortoises in East Harling and so approached them to ask if they were missing one,"
the rail rescuers told the Metro.
"Luckily tortoises can't get too far too fast."
Clyde's owner, Dillon Prest of Swallow Aquatics said the old tortoise was just looking for love.
"I think he smashed his way out to freedom because he wanted to find a girl tortoise," Prest told the Metro.
The randy tortoise had broken out of his pen in East Harling and went in search of a mate from the other side of the tracks.
"I guess he just wanted some female company, and he thought that Norwich was the right place to find some."
In an update on Tuesday the rail operator said that, despite the damage to his shell, the tortoise was doing well "if a little shell shocked" and would be returned home to the wildlife centre soon.