There are currently 63 six-sheets on the Heathrow Express estate, solely on platforms. The new rollout will bring digital sheetage to Heathrow Express walkways and escalators for the first time.
The rollout on Sunday (1 November) will also bring full motion digital panels to Heathrow Express lifts in all five terminals.
The panels were installed by Esprit Digital, the company that manufactures digital escalator panels on the London Underground.
Heathrow Express is the high-speed rail service connecting Heathrow Airport with Paddington station in central London.
Passenger numbers on the Heathrow Express are expected to exceed 5.5 million in 2009, with a mix of business (62%) and leisure (38%) travellers.
It claims to provide advertisers' access to one of the most exclusive ABC1 audiences in the UK, with an AB profile of 68% of passengers.
The Heathrow Express outdoor media contract is under review, as are individual contracts for the rest of the BAA estate, which comprisess six airports. Applicants have until mid-November to submit their bids.
Last week, BAA reached a deal to sell Gatwick to the owner of City Airport.
In May, JCDecaux and BAA announced they were to terminate their £500m pan-airport ad contract in April 2010, seven years ahead of schedule.