Earlier this year Virgin introduced new Voyager and Pendolino trains to different parts of its rail network. In a passenger bulletin, the company has admitted factors such as thicker metal carriages and smaller windows on the new trains have a detrimental effect on mobile signal strength.
A Virgin spokesman said, "We are aware of the problems and are searching for a solution with our suppliers."
Broad Reach Networks, which supplies Virgin with wireless Lans for some of its first-class station lounges, is working with Orange and other operators to solve the problem.
Broad Reach chief executive Magnus McEwen-King said the problems faced by Virgin would be experienced by other rail firms that buy new trains.
Broad Reach and Virgin are aiming to introduce wireless Lans on trains, but the service would have to be supported by GPRS and 3G networks interfaced to a landline connection, which requires Broad Reach's involvement with the mobile operators.
Virgin is expected to test a signal booster device for its carriages from October, in partnership with the mobile operators.