London 2012: Heathrow Airport trains delayed by fire
Trains from Heathrow Airport to central London were suspended for about 30 minutes after a fire.
Services on the Heathrow Express and Heathrow Connect, which links to Paddington, were suspended at 10:50 BST after a fire at West Ealing station.
First Great Western services into the capital were also delayed for one hour.
Airport operator BAA said it was expecting "an extremely busy day" with 125,000 passengers arriving ahead of the Olympic Games Opening Ceremony.
More than 2,000 Olympic competitors and officials are expected to arrive.
BAA said services were disrupted following the fire on a disused platform.
A BAA spokesman said: "The Heathrow Express and Heathrow Connect services experienced minor delays this morning following a fire at a platform of West Ealing station.
"Services are now back up and running."