Tendering for construction of the line is due to start in October and the work is expected to take seven years to complete. The project, which will be funded mainly by loans, has an estimated economic internal rate of return of 12.95% and a financial internal rate of return of 4.59%.

The initial 23.5km section of the Purple Line opened in August 2016 from Khlong Bang Phai to Tao Poon. The southern extension will comprise a 12.6km underground section with 10 stations and an 11km elevated section with another seven stations. Two of the stations at Bang Pakok and Rat Burana with have park-and-ride facilities with space for around 3000 cars.

The extension will connect with a planned extension of the Orange Line at Phan Fa, an extension to the Blue Line which is under construction at Wang Burapha and the planned Dark Red Line and the existing Dark Green/Silom Line at Wong Wian Yai.

Ridership on the extension is forecast at 477,098 passengers per day.

Thailand’s transport minister Mr Arkhom Termpittayapaisith says more metro projects will be submitted to the cabinet soon:
• Orange Line: 16.4km extension west from Cultural Centre via Phan Fa to Taling Chan (Baht 121bn)
• Blue Line: 8km extension from Bang Khae west to Phutthamonthon Sai 4 in Nong Khaem (Baht 21.1bn), and
• Green/Sukhumvit Line: from Khu Khot north to Lam Luk Ka (Baht 12bn) and from Kheha Samut Prakan south to Bang Pu (Baht 13.7bn).

For more detailed information about metro projects in Asia, subscribe to IRJ Pro.