TRAINS providing the premium fare Heathrow Express service between London Paddington and the terminals at Heathrow Airport have been withdrawn for emergency technical checks.

The Class 360 units usually used for the parallel stopping Heathrow Connect service have been drafted in as replacements, but as a result there are no Heathrow Connect services running. Local passengers are being advised that Great Western Railway suburban services will be making additional station calls and that extra trains will run, but that passengers between Hayes & Harlington and the airport will have to use Route 140 buses, on which rail tickets will be accepted. HEX tickets are also being accepted on the Piccadilly Line to Heathrow stations.

The Class 332 fleet used for Heathrow Express was built by Siemens, whose engineers still carry out maintenance of the trains at Old Oak Common depot. In a statement, airport-owned Heathrow Express said "a technical issue has been identified which has resulted in the majority of the Heathrow Express trains being taken out of service as a safety precaution. The trains have now been recalled as a precaution. Over the coming days each train will be thoroughly inspected by a specialist team at the Old Oak Common depot, to provide assurance".

No details of the 'technical issue' have been revealed, but HEX said the problem had emerged during routine maintenance. Aslef, however, has alleged that a crack in an underframe was found on Sunday, and that it was this discovery that triggered the fleet-wide checks.

Heathrow Express director Fraser Brown said: “While we regret the inconvenience this will cause to our customers and airport colleagues, safety remains our top priority. We are working with Siemens engineers, who manage our depot site and the maintenance of our trains, to understand the extent of this issue. When we are aware of what we are dealing with, we will be able to make a decision on when a full service will resume."

HEX has reduced its standard 'Express Class' fare from £22 to £17 while the service is being provided by Heathrow Connect units, which have fewer facilities on board. Business Class passengers who have booked ahead are receiving refunds.