The BBC said "The body scanner being unveiled at Paddington can detect hidden weapons and explosives and was developed by an American company.
The trial will aim to have only a minimal impact on the flow of passengers on the Heathrow Express and, if successful, could see other stations using the scanners.
Other technology being tested includes advanced closed circuit television systems programmed to sound an alarm when they spot suspicious behaviour.....
"Transport Secretary Alistair Darling unveiled the trials in the autumn. It followed a three-day conference which examined transport security in the wake of the 7 July bomb blasts, in which 56 people, including four suicide bombers, died and 700 were injured."
It was previously believed that full "airport-style security" isn't possible at stations in the UK and on London Underground stations because of the huge numbers of people using them every day. It will be interesting to see how these trials go.