The first Elizabeth Line train was put on the tracks in a trial run through Wembley before its launch for passenger use in May.
The "state of the art" carriages will have air conditioning, CCTV and live travel information as part of a major Crossrail upgrade.
The new "Class 345" trains will enter service in May on Transport for London rail networks between Liverpool Street and Shenfield, with the first trains being seven carriages and 160 metres long to fit existing platforms at Liverpool Street.
The 200 metre-long trains will have nine carriages which will be able to carry up to 1,500 people and will be introduced from May 2018, initially between Heathrow and Paddington.
Val Shawcross, deputy mayor for transport, said: "These state-of-the-art trains will play a key role in London’s future – helping to deliver a modern, world class transport system through the new Elizabeth line and enabling London’s transport network to cope as our population rises.
"Alongside the new and modernised stations they will serve, the new trains will transform travel across London and will make life better for millions of Londoners."
By May 2019, the Elizabeth Line will be fully open and extending to Reading and Heathrow Terminal 4 as well as between Paddington and Abbey Wood, Liverpool Street to Shenfield and Paddington Main Line to Heathrow Terminal 4.
Transport for London shared the news on social media after a successful trail and said: "The first Elizabeth Line train arrived in London this morning from the Midlands for testing and driver training."
The new trains will be equipped with WiFi and trains will be energy efficient after new builds will use up to 30% less energy than previous trains.
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