No more overbooking: Korea’s rail fleet upgrade with PTV Visum

Since the launch of the Korea Train eXpress (KTX) in 2004, South Korea has undergone a transportation revolution. The high-speed rail system has drastically reduced travel times and strengthened regional connectivity, transforming mobility patterns across the country. However, after more than two decades of operation, the first-generation KTX-1 trainsets are approaching the end of their service life.

To ensure the continued efficiency and reliability of Korea’s high-speed rail network, national rail operator Korail is implementing a fleet replacement strategy. This strategy is powered by advanced transportation modeling using PTV Visum for public transportation. This cutting-edge simulation tool enables Korail to optimize train schedules, analyze capacity needs, and support government funding approval through data-driven decision making.

By integrating Korail’s Digital Traffic Platform (DTP) with PTV Visum, Korail has developed a sophisticated analytical framework that:

• examines real-time train operations through time-space diagrams

• optimizes rolling stock utilization through block diagram analysisand.

• and determines the exact number of trainsets required through line blocking methodology.
  

Why it is urgent to replace KTX-1 fleet

The KTX-1 trains currently operate on five major corridors with a total of 43 stations. The trains make 188 daily trips, including the Gyeongbu Line (123 daily trips) and the Honam Line (30 daily trips).

Despite the efficiency of the existing network, passenger demand has outstripped seat availability, resulting in severe overcrowding. Currently, the seat load factor exceeds 112%, meaning that there are more tickets purchased than seats available. As a result, KTX frequently experiences overbooked trains and passenger dissatisfaction.

To address this issue, Korail has proposed to increase the number of daily services:

– Gyeongbu Line: +14 additional daily trips
– Honam Line: +8 additional daily trips
– Total expanded daily operations: 210 daily trips

However, it is not possible to increase services without additional trainsets as the current fleet cannot support the proposed expansion of operations. To meet future demand, Korail has determined that the fleet size must increase from 46 to 51 trainsets.

Korail’s Digital Traffic Platform and Visum

Korail has developed a Digital Traffic Platform (DTP) that integrates network modeling, demand forecasting and fleet management tools. This platform enables

• Modeling of current and future rail demand using data from the Korea Transport Database (KTDB).
  
• Simulation of train operations using time-space diagrams.
  
• Optimization of fleet utilization and deployment through Block and Line Blocking analysis.

To support fleet replacement decisions, Korail mapped its entire rail network with PTV Visum. This included the integration of existing and future KTX routes, traffic zones based on regional economic activity and population density, and an Origin-Destination (O/D) matrix for passenger flow analysis.

Visum analysis of fleet requirements

Korail used PTV Visum to conduct a step-by-step analysis of its fleet requirements:

Step 1: Time-Space Diagram for Operations Optimization

The first step in the analysis process was to develop time-space diagrams that show train movements over time and across different corridors. This helps identify congestion points, optimize train intervals, balance passenger demand between peak and off-peak hours, and assess potential bottlenecks that could impact future service expansion.

By analyzing train operations from departure to arrival, Korail was able to determine the optimal scheduling adjustments needed to improve service efficiency.

Step 2: Line Blocking Analysis for fleet size determination

The next step in the mvling process was Line Blocking Analysis that allowed Korail to optimize the number of trainsets required for the expanded service plan. It was done by grouping train operations into blocks to minimize empty runs, balancing train rotation schedules across lines, and improving the efficiency of depot layovers and train maintenance scheduling.

By using graph theory to optimize trainset allocation, Korail validated that 51 trainsets were needed to support the increased service frequency.

Step 3: Block Diagram Analysis for Fleet Scheduling Optimization

After analyzing Line Blocking, Korail performed a block diagram analysis, a critical step in optimizing fleet utilization. This allowed for more efficient assignment of trainsets to service blocks, minimization of idle time to maximize operational efficiency, and improved train scheduling strategies based on passenger demand.

Through simulated scheduling scenarios, Korail confirmed that an increase from 46 to 51 trainsets was necessary for sustained operational efficiency and reliability.

Results: Key benefits of the projects

With the support of PTV Visum, Korail is now on track to replace the KTX-1 fleet. This will increase daily seat capacity by 11.8%, reduce overcrowding and improve service reliability through higher train frequencies and improved scheduling.

In addition, optimized fleet deployment using time-space and block diagram analysis, along with line blocking techniques, will improve rail infrastructure efficiency and reduce operating costs.

Korail has also integrated cloud visualizations from PTV, that dynamically simulate rail operations. These visualizations provide an intuitive representation of rail network flows, train trajectories and real-time scheduling. They enable planners to visualize train movements across the network, providing critical insight into system-wide performance and efficiency.

By integrating Korail’s Digital Traffic Platform (DTP), PTV Visum and PTV’s cloud visualizations, Korail has developed a robust methodology. It ensures accurate forecasting, optimal fleet allocation and efficient scheduling for the future of Korea’s high-speed rail network.