Thailand expects to select a consortium by January to build a 225 billion baht ($6.9 billion) high-speed rail link connecting three international airports, one of the largest transport projects in its history.

The agency overseeing the plan, the Eastern Economic Corridor Office, aims to make as much progress on the project as possible ahead of elections due from February next year, said its Secretary General Kanit Sangsubhan. Some 31 firms, mostly from Thailand, China and Japan, are studying the project’s terms.

One area of assessment will be “how much the consortium will ask of the government for co-investment,” Kanit said in an interview in his office in Bangkok on Monday.

The military government in power since a coup in 2014 has championed infrastructure investment to try and lift the pace of Thai economic growth toward the levels achieved in neighboring nations. But it remains to be seen how much of its agenda will remain intact after general elections, amid signs of opposition to elements of the push.

The Eastern Economic Corridor is a 1.7 trillion baht plan to add infrastructure and advanced industries in the provinces of Rayong, Chachoengsao and Chonburi. The rail link would run between Bangkok’s two international airports and another near the tourist hot-spot of Pattaya, the U-Tapao International Airport in Rayong.

Talks are underway for Airports of Thailand Pcl to be a partner and shareholder in the planned expansion of U-Tapao, Kanit said.

The SET Construction Services Index of 19 firms has dropped about 21 percent in the past year, compared with a 3 percent advance in the overall Thai stock market, despite the government’s focus on infrastructure.

The index may start climbing from the fourth quarter through to the middle of 2019 as Eastern Economic Corridor projects make more progress, said Raenoo Bhandasukdi, an analyst at KT Zmico Securities Co. in Bangkok.