Transport for London has released renderings and a video showing the trains originally designed by Barber and Osgerby for the city's east-west rail link Crossrail (+ movie).

The trains will transport up to 1,500 passengers at a time across the UK capital. Each one measures 200 metres, the length of two football pitches or the equivalent of 18 Thomas Heatherwick-designed Routemaster buses.

London design duo Barber and Osgerby were behind the initial designs for the trains, which will have wide interconnecting gangways and three double doors on each side of each carriage.

Images released by TfL last week show a variety of seating types, including fold-away chairs to create space for wheelchair users. Purple upholstery and livery matches Crossrail's colour for the London Underground map.

Passengers will be able to pass through from carriage to carriage along the entire length of the train.

"You could get on at Moorgate [station], walk through the train and get off at Liverpool Street without the train moving," Jay Osgerby told Dezeen during an interview earlier this year.

Manufactured by UK firm Bombardier, the trains are designed to be as efficient as possible. They will include energy management systems for controlling lighting and air conditioning, which will re-generate energy back into the supply when braking.

Barber and Osgerby were appointed to design the trains in July 2014, but the duo told Dezeen that their role has altered slightly since then.

"We did design the entire thing," said Osgerby. "But ultimately our role has become less about the industrial design and more about the creative direction, because a lot of the industrial design was already done. It was already considered as part of the tender that Bombardier had."

"So I would say that we have had the kind of creative influence and we remain creatively involved in the whole project, but we're not claiming to be the design team on it," he added.

Earlier this year, TfL announced it would be working with Bombardier on the final designs for the trains with the first due to be delivered in May 2017.

A carriage has already completed testing at Bombardier's train manufacturing plant in Derby.

This prototype will now be used to refine the design and the manufacturing techniques for the 594 carriages needed for the 66 Crossrail trains.

The first section of the cross-capital rail line is due to open in May 2017, with services running from Shenfield in Essex to Liverpool Street in central London.

Other parts of the project will open in stages. Full operation is planned for December 2019, when the east London section will connect to Reading and Heathrow Airport in the west.

The construction of the rail line involves the building of new stations, and upgrading existing stations and adjacent public spaces in central London.

The roof garden above Foster + Partners' Canary Wharf station was finished earlier this year, while work continues on the plaza below the Centre Point tower as part of the expansion of Tottenham Court Road station.

Earlier this month, Eurostar revealed a fleet of trains by Italian studio Pininfarina that will serve a new range of European cities.

Images courtesy of TfL.