Their Majesties the King and Queen on Saturday presided over a royal ceremony organised to mark the official opening of Chaloem Ratchamongkhon Line, a new extension of the Blue Line, amid a large crowd of people who turned up to greet them.
Consisting of 20 stations, the extension of the electric rail route spans 11 kilometres from Sanam Chai station in Phra Nakhon district to Lak Song station in Bang Khae district of Bangkok.
His Majesty the King, on the occasion of his coronation last year, granted the official name of Chaloem Ratchamongkhon to the new Blue Line extension.
Chaloem Ratchamongkhon means "the celebration of an auspicious occasion of kingship".
The King and Queen arrived at about 5.35pm at the Sanam Chai station where a large crowd of yellow-clad people were waiting to catch a glimpse of the royal couple.
After the opening ceremony, Their Majesties rode an electric train from the Sanam Chai station to Lak Song station, which took roughly 12 minutes.
Much to the well-wishers' surprise, Their Majesties stopped to greet people waiting at the station before they got on the train.
Even more remarkable, about 60 well-wishers were permitted to ride on the same train with Their Majesties, all of whom afterwards said they were awe-struck.
Her Majesty the Queen invited them to get on board saying: "Let's ride together".
At the end of the special ride, Their Majesties signed autographs and wrote messages on portraits of them which people had brought along.
In one of the messages, His Majesty wrote: "Thailand and its people should keep up love, best wishes and security."
Among other messages written by the King either on his portraits or on yellow shirts brought by the people were: "Thai people have a culture and a moral standard."
"Do good deeds and be happy. The nation will thrive."
Another message written by the King read: "Think positive, do good. Be patient, be united."
Nonthakon Duangdara, a nine-year-old boy from the Lat Phrao area of Bangkok, said his family was taking him on a trip to the Museum of Siam on Sanam Chai Road when they got the rare chance to ride on the same train as Their Majesties.
He and seven other family members joined the ride.
He said he had never before seen Their Majesties up so close and being able to catch a glimpse of them in the flesh left a big impression. "It's like a dream come true," he said.
Somchok Phonrak, 68, travelled all the way from the southern province of Phuket to Bangkok to join the well-wishers who turned up in droves at Sanam Chai station yesterday.
He said he had learned from the news that Their Majesties would be present at the station for the opening ceremony and wanted to be part of the historic event. In the end, being able to ride on the same train as Their Majesties exceeded Mr Somchok's wildest expectations.