The public have been given the chance to travel on a "state of the art" train, which will serve London's new Elizabeth Line.
Part of a fleet of 66, the train, which will serve the new line when a rail tunnel opens through central London, has been operating between Liverpool Street and Shenfield.
The Elizabeth Line will serve the West End, the City and Docklands and run from Reading and Heathrow in the west across to Shenfield and Abbey Wood in the east, through 40 accessible stations.
When fully open in December 2018, the Elizabeth Line will increase central London's rail capacity by ten per cent, carrying more than half a million passengers per day.
The Mayor of London, Sadiq Khan, said: "I'm delighted that our first state-of-the-art Elizabeth Line train has entered service on the TfL Rail service.
"It gives Londoners a first look at a new service that will transform travel across London and the south east when the line opens.
"The Crossrail programme remains on time and on budget, and the huge success of this project shows how vital it is for the whole of the country that we also push ahead with Crossrail two."
More than 10 trains will be introduced on the route by the autumn and will initially be 160 metres long and made up of seven carriages, later to be extended to nine and able to carry 1,500 people.
The trains will offer air-conditioning, walk through carriages, dedicated wheelchair spaces and additional multi-use spaces for buggies and luggage, and improved travel information for passengers to plan their onward journeys, among others.
Mike Brown MVO, London's Transport Commissioner, said: "This is an important day for rail travel and for the millions of passengers who will use the Elizabeth Line when services start in December next year.
"The trains are a great showcase of British design and manufacturing with air-conditioning, interconnected carriages, improved customer information and dedicated space for wheelchairs.
"The introduction of this first train gives customers a feel for the huge improvements that are to come when the Elizabeth line opens."
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