Work on Thailand's first rail tunnel under the Chao Phraya River is expected to finish by Dec 5 this year and will connect with the Sanam Chai station train to be developed into a "palace hall" on the extended Blue Line rail route.
More than 75% of construction on the east side, also known as Eastbound, of the Blue Line is now complete.
Transport Minister Arkhom Termpittayapaisith says he is impressed with progress, but also looking forward to seeing the elegantly decorated Sanam Chai station, which will connect to Itsaraphap station on the west side of the river via a 200-metre tunnel.
The two are among 13 stations on the 14-kilometre extended Blue Line running from Hua Lamphong, Bangkok's main railway station and the first station on the Blue Line subway, to Bang Khae.
The tunnel, which is built about 10 metres under the river, promises to be an exciting new feature in Bangkok, which was introduced to the skytrain 16 years ago.
Mr Arkhom said Sanam Chai station is also likely to emerge as a grand new landmark for the city.
"Sanam Chai will be the first station which uses innovation to improve its design," he said.
A mix of modern railway station and decorative architectural features, passengers will feel as if they are walking into a "palace hall", he said.
National artist Phinyo Suwankhiri has designed the station from impressions of royal palaces in the Rattanakosin era, the current royal period. Commuters will be amazed by the scenes of grandeur envisaged for the station, including traditional Thai architecture, Mr Arkhom said.
Sanam Chai is not just a railway station with an underwater tunnel -- a symbol of high technology -- but with its palace-style, it will hold cultural and historical value, he said.
The minister said Sanam Chai station is likely to emerge as a tourist spot. It is located near Wat Pho, a Buddhist temple complex in Phra Nakhon district, Museum Siam, the Grand Palace and the Temple of the Emerald Buddha, all of which are major attractions in Bangkok's old zone, he said.