Starting in 2032 with the Ui-Sinseol Line, the Seoul city government will push to expand adoption of a "wireless communication-based train control system." This system can narrow subway headways compared to the current method. Through this, Seoul plans to reduce average subway congestion by 20%.
On the 26th, the Seoul city government announced an "innovative plan to improve urban rail congestion" that includes these details.
Daily ridership on the Seoul subway is about 5 million people. It increased from 3,865,000 people in 2024 to 4,925,000 people last year. Congestion in some sections has been rising in step with the increase in ridership.
During the morning hours on Line 9, congestion reaches 182.5% at Noryangjin Station. Line 2 Sadang Station (150.4%) and Ui-Sinseol Line Jeongneung Station (163.2%) are also high. A congestion level of 100% is a full load, and 150% or higher is classified as packed.
In response, the city plans to introduce a new train control system to ease subway congestion.
Most subways in Korea currently use the "track circuit method," which identifies train positions by sending electric signals through the tracks and detecting locations by block. Positions identified by block have limits when it comes to reducing headways. On Line 9, the safe distance between trains is fixed at 400 m, and on the Ui-Sinseol Line it is 240 m or more.
The "wireless communication method" now being pursued identifies train positions in real time through wireless communication between trains and the control center. It dynamically controls safe distances according to train movements. Technically, it is said to be possible to reduce the distance between trains dramatically to as little as 25 m. The city said that by narrowing the intervals between trains, it expects about a 20% increase in capacity and relief of congestion.
The Sillim Line is already operating with KTCS-M, a Korean-style wireless communication method. Incheon Subway Line 1 is also planning an upgrade to the wireless communication method. Major overseas cities such as New York, London, Paris, and Hong Kong are likewise adopting the wireless communication method.
The city will first apply the wireless communication method to the Ui-Sinseol Line. The target timing is 2032, when the Ui-Sinseol extension is scheduled to open. With replacement investment for the Ui-Sinseol Line signal system planned for 2034, the plan is to minimize the input expense.
The city will begin detailed design in the first half of this year, reflecting the results of the review service, and after installing ground and onboard devices, it plans to complete the work with the opening of the extension in 2032. It will then push a phased transition for Line 9 and Line 2.
Yeo Jang-gwon, head of Seoul's Transportation Bureau, said, "Subway congestion is an issue directly tied to citizens' lives," adding, "Instead of relying only on facility expansion, we will proactively adopt innovative technologies such as the wireless communication method to improve the situation."