A GTX-A train approaches Suseo Station in Seoul as it heads to Dongtan Station in Gyeonggi Province, Jan. 5. Newsis

A high-speed commuter rail network connecting Seoul to Paju, in northwestern Gyeonggi Province, will begin service on Dec. 28, the transport ministry announced Wednesday.

The first section of the Great Train Express (GTX)-A commuter rail line opened in March, connecting Suseo in southeastern Seoul with Dongtan in Hwaseong, Gyeonggi Province.

The new section of the GTX-A line will run directly between Seoul Station and Unjeongjungang Station in Paju. The 40-kilometer trip will take just 22 minutes with the new train service, a significant improvement compared to the current 90-minute commute using a combination of subway, buses and transfers.

The section between Seoul Station and Suseo is still under construction.

The ministry said that the new connection will "drastically improve" traffic convenience in the northwestern part of the capital region.

To improve the new section's capacity, the ministry will add more train carriages during morning and evening rush hours. Trains will be spaced approximately six minutes apart, it said. It will also increase the number of trains for the Suseo-Dongtan section to 60 from 52 per day.

SG Rail, the operator of GTX-A, also plans to display various content on OLED screens inside the trains.

Baek Won-kug, vice minister for transport, stated that the latest section of the GTX-A line follows the launch of the Suseo-Dongtan section in March, which has attracted a growing number of passengers and is now recognized as the most convenient and fastest public transport option for the southern part of the capital region.

The latest section added to the GTX-A line is expected to improve public transit accessibility across the capital, Gyeonggi Province and parts of Incheon. The ministry hope the expansion will help alleviate the population concentrated in Seoul by making Gyeonggi Province more transit-friendly, encouraging a more balanced population distribution throughout the capital region.

"Once the GTX-A's Unjeongjungang-Seoul section starts operating, the northwestern area of the capital region will start to greatly benefit from the new level of convenience," Baek said.

SG Rail plans to run a train service along the Unjeongjungang-Seoul section the day before its official opening as part of an official ceremony.