A brand new Class 345 train has run into Paddington for the first time and testing will now take place as far as Reading and Maidenhead.
TfL tweeted the news from the Elizabeth line's official Twitter account on Tuesday.
The line, named in honour of the Queen, is expected to open in phases just before Christmas with passengers set to use 10 new state of the art stations across London and the south east.
The first stage will see Paddington’s new Elizabeth Station open and link with Abbey Wood via central London.
The first Elizabeth line trains came into service in east London between Liverpool Street and Shenfield in June last year.
The first Elizabeth Line Tube roundels were recently installed at stations across the capital.
New images were released of the purple TfL signs at Custom House, Farringdon and Tottenham Court Road stations ahead of Crossrail’s launch in December.
Crossrail, Europe’s largest infrastructure project, is 85 per cent complete and will run from Reading and Heathrow to Shenfield and Abbey Wood in the east.
When fully open in 2019, it will increase central London's rail capacity by ten per cent, carrying over half a million passengers per day.
It will travel through 42km of tunnels under London and is expected to carry 200 million passengers per year.