TFL has unveiled designs for the new Crossrail trains due to enter service from May 2017.
Constructed by Bombardier, each train be will be one and a half times longer than the longest Tube, with nine walk-through carriages providing space for 1,500 passengers, and four dedicated wheelchair spaces.
With just 50 seats per carriage, 1,050 of those 1,500 potential passengers would have to stand.
Running between Reading to the west of London and Shenfield to the east, the train's boast features including intelligent lighting and temperature control systems, and will use up to 30 per cent less energy through regenerating electricity back into the power supply when braking.
In language perhaps more befitting of a home furnishings catalogue than a local transport authority, TFL said: "The interior design and colour palette has been carefully selected to provide an accessible and welcoming environment. The design includes darker floors and natural finish materials that will wear in, and not wear out, ensuring they retain their high-quality feel for years to come. The light coloured ceilings also maximise the feeling of height and openness inside the new trains."
London mayor Boris Johnson said: "It's fantastic to think that these sleek new trains will soon be transporting millions of people across our great city and beyond. They're feature packed, eye-catching machines that showcase the best of British design and engineering. They'll add vital capacity to our rail network and will help to ensure our economy continues its onward journey full-steam ahead. The largest construction project in Europe is another tantalising step closer to becoming a brand new working railway for the Capital."
Rail Minister Claire Perry said: "I am delighted that these British-built trains have been designed with customers at their heart, with onboard facilities that are fit for a truly 21st century rail link. The spacious layout and longer trains will provide a significant boost to London's rail capacity, meaning better journeys for passengers, and transforming the way people travel between east and west. I look forward to seeing the first train off the Derby production line next year."