The first of a fleet of 66 brand new Elizabeth Line trains has completed production and has begun testing at Bombardier's Derby site.
The trains will begin service on the current TfL Rail route, between Liverpool Street and Shenfield, in May 2017. These will be a slightly smaller seven carriage, 160 meter train as a result of the slightly shorter platform at Liverpool street.
The full train length will be 200 meters, consisting of nine carriages, with a capacity of around 1,500 passengers. These begin service from May 2018 between Heathrow and Paddington.
Services at Iver station are due to begin in 2019 with up to four services an hour starting in the December.
The trains will have walk-through carriages, similar to the new Metropolitan line trains, as well as being able to regenerate electricity when the train brakes. This is expected to reduce energy consumption by up to 30%.
TfL are estimating that when the service is fully open, in 2019, it will carry as many as half a million passengers a day and boost the economy by billions, with plenty of new job creation as well as new homes being built.
Transport Minister, Lord Ahmad, said: 'The Elizabeth Line and its new trains are a great example of our commitment to improve passenger journeys by investing in one of the most ambitious infrastructure programmes ever undertaken in the UK.
'This investment will transform the way people travel across London and beyond. And it doesn't stop here.
'The Government is spending record amounts on upgrading the rail network, providing a huge boost to capacity to keep Britain moving, support economic growth and bring our country closer together.'
Once the trials are complete, the train will be unloaded of testing equipment and the interior will be fitted, ready to start carrying passengers from May 2017.