The new high-frequency suburban rail service for commuters named Great Train Express (GTX) is set to begin operation on Saturday, marking a watershed moment in the evolution of Seoul's public transportation.

President Yoon Suk Yeol said Friday the GTX network will grow to become the South Korean equivalent of the Crossrail of London and its suburbs in the United Kingdom, and the RER centering around Paris.

Those using the commuter rail network to travel from Suseo Station in southern Seoul to Dongtan in Gyeonggi Province, will enjoy a short travel time of 20 minutes, or one-fourth their travel by bus, Yoon told some 250 participants at a ceremony held in Suseo Station on Friday.

Yoon compared the moment to the historic opening of the Gyeongbu Expressway -- a 416-kilometer highway connecting Seoul and Busan -- in 1970, and of the high-speed train KTX in 2004, as he came to commemorate the opening of the new suburban rail system.

"Today marks an important day for the transport revolution in South Korea," Yoon said.

He also stressed that the new commuter railway will stimulate economic growth in areas near stations and address the housing supply shortage in the capital city.

GTX will "trigger a revolutionary improvement of urban competitiveness" for the cities within the Greater Seoul area, Yoon said, adding, "GTX will shorten the travel time between cities and prompt interactions of people in different cities."

Following the ceremony, Yoon boarded a train for a test run Friday, traveling from Suseo station to Dongtan.

The 34.9-kilometer segment of GTX-A that opened Friday has three stations -- Suseo, Seongnam and Dongtan. Their construction was completed in 2023.

Beginning Saturday at 5:30 a.m., suburban trains will run between Suseo Station and Dongtan. The last train will arrive at each station at 1 a.m. the next day.

Each ride will cost up to 4,450 won ($3.30) depending on the distance for the traveler, with its basic fare for 10 kilometers of distance set at 3,200 won. Its ticketing system is integrated with Seoul's subway network, so travelers will not have to pay for rides on the subway and GTX separately. However, Seoul City's monthly transit pass, "the Climate Card," is an exception, as the pass is mostly inapplicable in Gyeonggi Province.

A train will come in every 17 minutes during peak hours, and 20 minutes or more during normal hours.

The first line of the GTX system, GTX-A, will be as long as 82.1 kilometers, connecting Paju, Gyeonggi Province, with Seoul Station and Dongtan when construction is complete in 2028.