Heathrow Express’ Class 332 fleet will remain out of service “for the foreseeable future” following the discovery of a defect on one of the trains earlier this week.
The fleet was recalled on February 29 so that a full inspection could be carried out after a fault was found on one of the carriages.
Heathrow Express has now announced that the trains won’t be returned to service any time soon after engineers found a “structural defect” on the underside of a number of other trains.
Engineers have been flown in from Spain and Germany to assist the inspection and maintenance process.
Heathrow Express director Fraser Brown said: “The safety of our customers and colleagues remains our top priority.
“We apologise for the inconvenience this has caused so far, and assure passengers that we are doing everything we can to return to running a full and safe service, as quickly as possible. We would like to thank all our customers for their patience.”
Class 360 Heathrow Connect units will operate a replacement service between Paddington and Heathrow while the investigation takes place. Heathrow Express ticket prices will be reduced in the meantime.