[7] After the development of HEMU-430X, Hyundai-Rotem and Korail signed an agreement in December 2016 for supplying high speed trains that are electric multiple units, the first of its kind in South Korea in commercial service (the HEMU-430X is also an electric multiple unit, but it is not for service and mass production).

[12] Elements of the EMU-320 had to be re-designed due to serious concerns about excessive noise levels in the cab and passenger compartments, a key reason for its delay.

Measures including improving the pantograph's shape and adding sound insulation to the ceiling and floor have been taken to reduce noise levels.

[13] The two pre-series sets built by Hyundai Rotem following a 2016 contract were delivered to Korail in November 2023 and were expected to begin operations in 2024.

Seats in both first and second class will be capable of being rotated to face the direction of travel from a single control unit.