York, England - The blue locomotive, called Bittern, raced up the East Coast line from King's Cross to York with 250 passengers on board after being granted permission to exceed the 75mph steam train limit.

The record speed, 126mph, remains unbroken. That was achieved by an almost identical train, the Mallard, in 1938. Only six A4s survive.

They are being reunited at the National Railway Museum in York from Wednesday in an event called the Great Gathering.