The trial  was scheduled for Aug 12, which is Mother's Day.

However, the contractors had advised they would not be able to complete the work by that date. So the first run had been rescheduled for Dec 5, or Father's Day, His Majesty the King's birthday.

Under the contractual agreement, building of the 28km route from downtown Bangkok to Suvarnabhumi must be completed by November.

It was now expected that the Airport link, which connects Phaya Thai and Makkasan areas to the international airport, would enter service in March next year, Mr Thawalrat said.

The State Railway of Thailand has said the fare will be 150 baht for passengers taking non-stop trains, and  between 15 and 45 baht for trains that stop at every station.