Transport for London (TfL) has revealed that the first of 10 new Elizabeth line trains being built in Derby has left its production line and is undergoing final checks on the on-site test track.

The train will soon undergo a period of trials on train lines near London and on the Elizabeth line itself, before entering passenger service later this year.

TfL said the milestone came as the Elizabeth line celebrated its four-year anniversary. It has become the UK’s single busiest railway service, with more than 850 million passenger journeys made since it opened in May 2022. When all the new trains are complete, the total Elizabeth line fleet will be almost ten miles long, with a total capacity of around 120,000 people: more capacity than London’s Wembley stadium.

The 10 new Aventra Class 345 trains are being delivered with Government funding to help meet growing demand on the line, increasing capacity and serving HS2’s new Old Oak Common station in the future.

The trains are being built by Alstom at its Litchurch Lane factory in Derby, a city that has been at the heart of Britain’s railway heritage since 1839. Derby Litchurch Lane Works opened in 1876 and is now the UK’s only remaining facility capable of designing, engineering, manufacturing and testing trains from scratch.

TfL said the work in Derby demonstrated how investment in London’s transport infrastructure delivered benefits beyond the capital, with its supply chain supporting almost 40 companies totalling more than 1,000 employees.

Each nine-carriage Elizabeth line train leaving Alstom’s 150-year-old factory contains five miles of welding, 50 miles of cabling, and more than 47,700 screws and 31,700 bolts. The new trains will be manufactured, tested and introduced into service over this year and next.

TfL revealed that data from Excel London showed how the Elizabeth line was driving demand across London’s economy, particularly in business tourism. It added that this “growing popularity” made the introduction of new trains to meet demand a priority.

Trish Ashton, Director of Rail at TfL, said: “More than 850 million customer journeys have now been made on the Elizabeth line, and it’s fantastic to see the first of the ten new trains leaving the factory. This is an important milestone in our journey towards increasing capacity on the line, meeting the growing demand for increased connectivity that we deliver for hundreds of thousands of customers every day.”

Seb Dance, Deputy Mayor of London for Transport, said: “The Elizabeth line is a perfect example of how quality transport infrastructure can unlock opportunities for the people and places it connects, with this vital work in Derby showing how investing in the capital doesn’t just benefit Londoners but drives wider economic growth across the country.

“As these fantastic new trains leave the factory to help meet growing demand on the line, the Mayor and I are excited to continue working hand in hand with TfL and the Government to unleash the full potential of our transport network, as we continue building a more prosperous London for everyone.”

Andy Butters, Managing Director of Derby Litchurch Lane Works, said: “Seeing the first of our new Elizabeth line Aventra trains roll off the production line in Derby is a proud moment for everyone at Litchurch Lane. This milestone reflects the skill, dedication and craftsmanship of our teams, who are proudly building additional trains for one of the UK’s most successful railway services.

“These new trains will help meet growing demand on the Elizabeth line while supporting highly skilled jobs in Derby and our nationwide supply chain. It’s a powerful example of how investment in London’s transport network delivers real economic benefits across the UK, with Derby continuing to play a central role in Britain’s rail industry – as it has done since 1839.”

Jeremy Rees, CEO of Excel London, said: “Without doubt, the Elizabeth line has been transformational for the events industry, removing the friction of travel across the city and reviving London’s business tourism economy. From our own independent research, we have seen a 20 per cent increase in visitor numbers to Excel London as a direct result of the Elizabeth line and leading to record-breaking attendances for many of our flagship trade shows.    “The most significant change though has been the increase in visitor durations – now an average of 7.5 hours – driven by faster journey times encouraging guests to stay longer, network more extensively, and conduct additional business.”