Newly refurbished trains are being introduced by Heathrow Express as part of a £16 million investment.
All trains will undergo a complete refit covering both Express and First Class carriages.
The first refurbished carriages entered service yesterday with the upgrading project due to be competed by April 2013.
Express Class improvements include revised seating layouts, improved luggage racks and lighting and the installation of power sockets in seats.
First Class carriages have been refined with increased comfort and exemplary service offered to reflect the airline experience, the company said.
Managing director Keith Greenfield said “Our new fleet will ensure that our customers receive the most relaxing and convenient travel experience possible.
“I am very proud to unveil our new trains – the result of three years hard work.
“Our new design and technology innovations twinned with excellent service initiatives mean that we offer customers the fastest, most sophisticated travel choice to and from London Heathrow.”