The line was built to ensure southeast Seoul (or Gangnam area) and southern Gyeonggi-do have high-speed rail connections.

[2] The first stage, to be realised by 2015, would involve two branches from the Gyeongbu HSR, one of which would lead to a second Seoul terminus at Suseo in the southeast part of the city.

[4] The line was to run in a tunnel at a depth of 50 m (160 ft) between Suseo and Dongtan, and construction with a budget of 4.18 trillion South Korean won was foreseen to be complete in 2015.

[6] The government set out a timeplan, according to which detailed design was to commence immediately, and construction was to take place from the second half of 2011 until the end of 2014.

[8] On September 1, 2010, the South Korean government announced a strategic plan to reduce travel times from Seoul to 95% of the country to under two hours by 2020.