Thailand expects to complete its first high-speed rail network linking the country to China through Laos in 2030, a long-delayed project officials have touted as key to furthering bilateral relations and trade between the two nations.

The construction of the first phase linking Bangkok and Nakhon Ratchasima province is currently at about 36% completed, according to Jirayu Houngsub, a government’s spokesperson. The design for the second phase that will extend the rail line to the northeastern border province of Nong Khai has been finalized and is ready to be submitted to the cabinet for approval, he said on Wednesday.

In all, the rail line is 609 kilometers (378 miles) long and is estimated to cost 434 billion baht ($12.9 billion). The Thai network will be connected to the Laos-China line via a bridge built over the Mekong River.