Countries within the Greater Mekong Subregion (GMS) will become better connected following a deal to build a high-caliber train network in the area.

On Friday, China and Thailand inked a memorandum of understanding (MoU) on railway cooperation, agreeing to jointly build Thailand's first standard-gauge railway lines with a total length of more than 800 km, which has been approved by the National Legislative Assembly of Thailand.

The project is estimated to cost around $10.6 billion and will connect northeast Thailand's Nong Khai province, Bangkok and eastern Rayong province.

"This is the expansion, extension and further confirmation of the previous agreement that the Chinese and Thai governments reached last year," said Chinese Premier Li Keqiang, who attended the fifth summit of the GMS Economic Cooperation held in the Thai capital on Saturday.

Li said he hoped the cost-effective new railway lines would benefit neighboring countries if extended to other places in the region.

The GMS Economic Cooperation Program, launched in 1992 by six countries along the Mekong River – Cambodia, China, Laos, Myanmar, Thailand and Vietnam, is aimed at pooling joint efforts to improve regional infrastructure, enhancing trade, investment and economic growth. China's total trade turnover with the other GMS countries topped $130 billion last year.

The lines will contribute to the rapidly growing regional economy that is the GMS, said Lei Zhuning, deputy head of the Southeast Asia Research Institute at Yunnan Academy of Social Sciences.

"Regional exchanges at the government and non-government levels in the GMS have been quite popular these years, so the new lines, once connected, will further bolster that fervor," Lei said.

The new lines, likely to be connected with the railway linking China and the Laos in the future, form a key project of the Trans-Asian Railway and will help build a fast transportation network within the GMS.

"The new trains in Thailand, a pivot of the Trans-Asian Railway, could be upgraded to high-speed trains in the future, which will connect the GMS countries at a much faster speed," said Song Qingrun, a research fellow with China Institute of Contemporary International Relations.

High-speed trains will help bolster logistics in the region, thus drawing more investment among the countries and forming bigger markets, according to Song.

"For instance, the network could woo more investors to the less-developed areas in Thailand, while Thai farm produce will be effectively transported to other countries in the GMS," Song said.

With the convenient high-speed trains forming an efficient network, the lines will also boost tourism along the routes, Song added.

But all of that, Song said, should be based on more openness and inclusiveness among the GMS countries.

"The trains are merely physical connections," Song said. "The GMS countries should work to break trade barriers to truly realize fast connectivity," he added.