Derby train-maker Bombardier has completed the first 100 carriages of an £869 million order placed by a UK train operator.
The Litchurch Lane firm is building a total of 665 carriages for Greater Anglia, which will serve commuter lines into London Liverpool Street.
In total, Bombardier is building 111 trains, which will be a mix of 10-carriage and five-carriage trains.
The firm has now reported that the 20th train is on the production line at its Litchurch Lane factory.
While new carriages roll off the production line, safety and performance tests are underway on built trains including tests on braking, traction and system functionality.

According to Greater Anglia, the first new train is due to start operating on its network later this year.
All of the new trains will be longer, with more seats, plug and USB sockets, free fast wifi, air conditioning, under-floor heating and better passenger information screens.
There will also be better accessibility features and four cycle spaces on every train.

Ian McConnell, Greater Anglia franchise and programmes director, said: “We’re looking forward to getting the first Bombardier train on our network.
“We’ve started replacing our diesel trains in the north of our network with new trains – and we know customers on the rest of the network are keen to see new trains on their routes too.
“Bombardier trains will replace all of our existing electric trains on commuter routes in Essex, Cambridge, Suffolk and Hertfordshire.”

Bombardier was awarded the contract to build and maintain the new trains back in 2016. The train it is supplying to Greater Anglia is the Aventra - a product designed and built in Derby.
Bombardier said it had expanded the Greater Anglia team at Litchurch Lane to speed up production.
Alan Fravolini, Bombardier’s project director for the Greater Anglia order, said: “We’re really cracking on with these great new trains for Greater Anglia.
“Production is accelerating with a strengthened team and we are all focused on passenger service as soon as possible.”
Greater Anglia is replacing every single train on its network with 169 brand new state-of-the-art longer trains.
Bombardier is building 111 trains and the other 58 trains are coming from Swiss manufacturer Stadler. The Bombardier trains have been procured by Angel Trains.
Greater Anglia is owned by Abellio - the company behind East Midlands Railway (EMR), which recently started operating the East Midlands rail franchise.