Deputy Prime Minister Somkid Jatusripitak has given assurances that the Thai-Chinese double-track railway project for the Bangkok-Nong Khai section will begin this year.
Thailand is on track to make a joint investment with China in the double-track rail route that spans Bangkok-Kaeng Khoi-Nakhon Ratchasima-Nong Khai, he said.
"We would like to accelerate concluding different viewpoints [between Thailand and China] to start the project soon," Mr Somkid said.
Thailand signed an agreement with the Chinese government last month to build an 873-kilometre double-track route from the northeastern province of Nong Khai to the industrial area of Map Ta Phut in Rayong province, passing through Bangkok.
China recently agreed to grant Thailand a 2% interest rate for a loan it will make to fund the double-track project.
The sections are part of the Pan-Asia Railway Network's central route, running from the southwestern Chinese city of Kunming through Laos, Thailand and Malaysia and ending in Singapore.
Transport Minister Arkhom Termpittayapaisith and Finance Minister Apisak Tantivorawong will soon visit China to talk railway investment, Mr Somkid said.
"Regarding contract signings for infrastructure projects, I would like the contracts to be completely signed in this first quarter in order to inject money into the system," he said.
"I'm quite sure investments in double-track rail and [Suvarnabhumi] airport will take place this year."
Mr Somkid said money from the 5-million-baht investment in each tambon under the stimulus package would be pumped into the system in the first half, with big-ticket projects and private investment to bear fruit in the second half.
An estimated 10 billion baht for 7,255 tambons nationwide will be taken out in the first quarter, he said.
Public and private investment will be the mainstay of the country's economic growth this year amid greater external headwinds, especially China's cooling economy.
In other news, Mr Somkid plans to speak with the Finance Ministry about relaxing rules blocking the government from taking out 300 billion baht in money accrued by local administrations to develop tourist destinations in rural areas.
Meanwhile, Mr Apisak said contracts for infrastructure megaprojects worth more than 900 billion baht would be sealed and 66.8 billion baht in investment budget drawn down in 2016.
The 66.8 billion baht will go to infrastructure projects such as double-track rail and development of Suvarnabhumi airport, with an additional 15 billion baht set for small projects, he said.
The Transport Ministry said 17 infrastructure megaprojects worth a combined 927 billion baht would be ready for bidding this year and next.
The projects include the 369-billion-baht double-track rail for Nong Khai-Bangkok-Map Ta Phut; the 51-billion-baht development of Suvarnabhumi airport's second phase; the one-metre-gauge rail projects for Saraburi to Jira intersection (132km, 29.8 billion baht) and Prachuap Khiri Khan to Chumphon (167km, 17.3 billion); the 25.9km Light Red Line (Bang Sue-Phaya Thai-Makkasan-Hua Mak, 44.2 billion); the 206km high-speed rail linking Bangkok and Hua Hin (98.4 billion); and the 196km Bangkok-Pattaya-Rayong high-speed line (152 billion).