Passengers wait for a train at Bukhansan Bogungmun Station on the Ui-Sinseol Line. [Herald DB]
Passengers wait for a train at Bukhansan Bogungmun Station on the Ui-Sinseol Line. [Herald DB]

Seoul will introduce a wireless Communication-Based Train Control (CBTC) system — a campaign pledge of the city's ninth elected administration — on the Ui-Sinseol Line, the capital's busiest light rail route, with peak congestion expected to fall by 22% as a result.

The Seoul Metropolitan Government announced Friday it is moving ahead with the "Ui-Sinseol Line Next-Generation Wireless Signal System Construction Project," the first step in its broader initiative to ease and modernize public transit congestion.

CBTC uses wireless communication to receive real-time train location data and dynamically adjust safe following distances between trains. By tracking train positions with precision, the system reduces travel times and improves punctuality.

The project is one of the flagship "public transit transformation" campaign pledges of the ninth-term Seoul mayor. The city unveiled its "Urban Railway Congestion Improvement Innovation Plan" in March, with the core shift being a move away from the conventional track-circuit signaling method — which detects train positions in fixed segments by running electrical signals through the rails — to a wireless communication-based approach. Under the new system, the control center tracks train positions in real time via wireless links and adjusts safe distances fluidly as trains move. This is expected to dramatically reduce headways, boosting capacity by about 20% and easing crowding.

Mayor Oh Se-hoon visited Seoul Metro's Second Control Center and the integrated control center construction site on April 6 to receive a briefing on the congestion-relief benefits and stressed the need to improve urban railway crowding.

Mayor Oh Se-hoon receives a briefing on the CBTC system during a visit to Seoul Metro on April 6. [Provided by Seoul Metropolitan Government]
Mayor Oh Se-hoon receives a briefing on the CBTC system during a visit to Seoul Metro on April 6. [Provided by Seoul Metropolitan Government]

While public transit infrastructure projects typically require years and significant investment, the CBTC transition leverages existing infrastructure to build a more efficient train operating framework, allowing riders to feel the benefits sooner.

The Ui-Sinseol Line, which carries heavy commuter, student and other daily traffic, currently records peak congestion of 165%. Once a data-driven train operation and control environment is in place, tighter scheduling will become possible, with congestion projected to fall by more than 20% and wait times expected to shorten as well.

Starting with the Ui-Sinseol Line, where administrative preparations are already underway, the city plans to extend the CBTC transition to Lines 2 and 9, where high congestion makes improvements most urgent.

The city will proceed in sequence through above-ground signal equipment installation, signal device retrofitting, performance verification, integrated testing and trial operations, with full CBTC service across the entire route — including the Ui-Sinseol extension — set to launch in 2032. With tighter scheduling raising average train speeds and cutting headways, peak congestion on the Ui-Sinseol Line is projected to fall from 165% to 143%, a reduction of about 22%. A congestion rate of 100% means the train is at full capacity; above 150% indicates passengers are packed in close contact.

Yeo Jang-gwon, head of the Seoul Metropolitan Government's transportation bureau, said the CBTC construction project is "a core initiative that will elevate the public transit operating framework to the next level through administrative innovation," adding that the city would "devote every effort to advancing the project so that the most tangible improvements in daily life — including reduced congestion — can be delivered to residents."


ikson@heraldcorp.com