It may not be a bullet train, but a steam locomotive made history this week as it became the first steam-driven train clocking 100 mph (161 km/h) on a British mainline track in over 50 years. On Wednesday, the coal-fired LNER Peppercorn Class A1 60163 Tornado hit its maximum speed on the East Coast Main Line (ECML) between Doncaster and Newcastle as part of its certification trials to allow it to operate on the UK rail network alongside its electric and diesel siblings.

Though it looks like something out of a period drama, the Tornado is actually one of Britain's most modern locomotives and its seemingly Victorian name is actually a reference to the Panavia Tornado fighter bomber flown by the Royal Air Force. Despite its old-fashioned appearance, it was only completed in 2008 after 14 years of construction at the Doncaster Works in the North of England.

It isn't the fastest steam locomotive ever built. That accolade belongs to the Mallard, which reached 126 mph (203 km/h) in 1938. Nor is it the only steam train operating in Britain. There are many functional ones in the hands of the National Railway Museum in York, private collectors, and charitable trusts. But it is the first proper steam locomotive to be built in Britain in over half a century and it incorporates a number of improvements and modern safety devices that allow it to make regular runs on mainline railways.

The Tornado was built by the A1 Steam Locomotive Trust as a way to correct an historic oversight. Forty-nine Peppercorn class A1 steam locomotives were built and operated in Britain in the decades after the Second World War and they gained a solid reputation for hard work and low maintenance. The last in a line of express passenger steam locomotives for the East Coast Main Line, the A1s could go 118,000 mi (189,900 km) between servicing – making them the cheapest locomotives in their class to run.

However, in the 1960s, the state-owned British Railways underwent a ruthless overhaul as steam was abandoned wholesale in favor of diesel and electric trains. In the frenzy of scrapping, all the A1s were cut up and melted down by 1966 without a single one preserved.

Then in the 1990s, the Trust got its hands on a set of the original plans and set out to build by hand the 50th A1 – not a museum replica, but a fully functional 105 ton (106.9 tonne) engine plus tender with a number of improvements and additional features to make it legal to operate on the main line alongside modern passenger and goods trains.

According to the Trust, the Tornado has already been operating since 2008, but it has been limited to speeds of under 75 mph (121 km/h). To fit in with other trains though, it must be able to do over 90 mph (145 km/h), so on the morning of April 12, it was rigged with diagnostic and recording gear and run at 10 percent over its planned maximum speed under the eyes of rail industry engineers and certification bodies.

"We are delighted to have completed the test runs that move us one step closer to 90 mph operations with Tornado," says Graeme Bunker-James, Operations Director for The A1 Steam Locomotive Trust. "This will allow us to ensure that the locomotive continues to haul trains on the busiest parts of the UK network allowing as many people as possible to enjoy traveling with Tornado. As part of these tests the locomotive operated at 90 mph for a sustained period and also achieved 100 mph under these special conditions and running with clear signals.

"We now have to analyze the results from the tests and then complete the necessary certification processes before the first 90 mph public operations can be undertaken. We hope to conclude this before the end of 2017."