Seoul Station train collision involving KTX, 287 passengers transferred
https://koreajoongangdaily.joins.com/news/2024-04-18/national/socialAffairs/Train-collision-at-Seoul-Station-involving-KTX-bullet-train-minor-injuries-reported-/2028329
The investigation of the root cause should be focused on if the ATS system(Automatic Train Stopping System) worked correctly or not.
Judging from the image on the article, Mugunghwa train crashed into KTX with slow speed. So, if the system had worked correctly, this accident could not have happened.