Tests have taken place on the East Coast Mainline to determine the highest speed steam trains can travel at safely.
Britain's newest locomotive, a Peppercorn class A1 named Tornado, hit the 100mph mark during test runs between Newcastle and Doncaster.
When travelling on the East Coast Main Line steam engines are currently limited to 75mph, but the intention is to run locomotives at speeds of up to 90mph.
This would help to reduce congestion and keep up with the high speed services on the busy UK rail networks.
Controlled testing found that steam engines will instead be able to travel at up to 100mph.
In common with other rail vehicles Tornado had to operate at 10% above its planned maximum speed to demonstrate a sufficient margin of safety.The tests were monitored by various rail industry engineers and certification bodies including organised by the A1 Steam Locomotive Trust, DB Cargo Rail and Network Rail.
Graeme Bunker-James, Operations Director for The A1 Steam Locomotive Trust, said:
We are delighted to have completed the test runs that move us one step closer to 90mph operations with Tornado.