The first train will be launched in early July, with improved WiFi that will offer a seamless single connection from train to plane, new media screens displaying flight data, and at-seat USB and plug sockets.
New Business First carriages will include a total of 44 seats, some with work tables. In total the train has the capacity for up to 374 seated passengers.
Each 160-metre-long train will be made up of 8 walk-through carriages, featuring a new livery and fresh upholstery.
The new fully-electric trains will be lighter and faster than the previous fleet, as well as being more fuel efficient.
It will also launch a new website and app, and is offering 10% off first bookings.
Heathrow Express’ Director Les Freer said: “Our new fleet of trains will offer the same fast, frequent and reliable Heathrow Express service for years to come.
“Complete with at seat USB power, fast wifi, ample luggage space and the option of Business First the new trains deliver a dedicated airport experience for both business and leisure travellers.”
The specially converted Class 387 trains will replace the current Class 332 fleet, which have been in service for 22 years carrying more than 115 million passengers over 44 million miles.
Originally built by Bombardier in Derby and having previously served customers on the GWR network, the specially converted fleet of Class 387s will be stored and maintained by GWR at their Reading depot as part of a partnership announced in March 2018.
The route takes 15 minutes between London Paddington and London Heathrow. There are plans to launch an onward travel service for customers, and the rail operator is currently looking to partner with a suitable ground transport handler.
Heathrow Express said it has seen a steady rise in passenger numbers, with around 45% of customers travelling for business.