The project is expected to cost Won 3.64 trillion and Molit says the government will begin negotiations with the consortium next month with the aim of entering a contract and beginning construction by the end of the year.
The section from Suseo to Dongtan has already been built and GTX trains will share tracks with SRT high-speed services as far as Samsung. The Dongtan - Samsung section is currently under construction and due to open in early 2021.
The entire 83.1km GTX Line A is set to open in 2023 and will run from Paju in the north of Gyeonggi province to Dongtan southern Gyeonggi serving major centres in Seoul.
Trains will operate at up to 180km/h on Line A, which is the first phase of the three-line GTX network.