Riyadh Metro's subway cars for Blue and Purple Lines run near one of the metro's 29 stations in Riyadh in this computer-generated image. Courtesy of Samsung C&T

Riyadh's new unmanned metro service, partly designed and built by Samsung C&T, began operations on Sunday.

The network includes six lines and spans a total of 176 kilometers of track. The Korean construction giant described the project as "the largest of its kind in the world."

Lines 1, 4 and 6 started running on Sunday while Lines 2 and 5 will start operating on Dec. 15 and Line 3 will begin operations on Jan. 5.

Samsung C&T was part of a consortium that oversaw the Riyadh Metro project. With Spanish builder FCC, Samsung joined in building Lines 4, 5 and 6. The network connects key areas in the Saudi capital including King Khalid International Airport and the King Abdullah financial district. The three lines cover a total length of 70 kilometers, including 24 kilometers on bridges, and connect 29 stations.

Riyadh Metro is one of Saudi Arabia's key domestic infrastructure projects aimed at helping it realize its Vision 2030, according to Samsung C&T. The objective, according to its official website, is a blueprint to diversify the country's economy, empowering citizens, and creating a vibrant environment for both local and international investors, all aimed at establishing Saudi Arabia as a global leader.

A Samsung C&T official said he anticipates the new metro service will not only advance Saudi Arabia's local economy but also raise the quality of life by reducing travel time in Riyadh.

A platform inside one of Riyadh Metro's stations / Courtesy of Samsung C&T

"It means a lot for us to be part of Riyadh's first metro construction project in the world's largest scale," Choi Young-hoon, vice president of Samsung C&T Riyadh Metro, said. "We met many obstacles but overcame them with our advanced construction technologies and know-hows."

Samsung C&T stated that, building on its success with the Riyadh Metro project, it plans to expand its portfolio to include infrastructure projects such as power stations in the Middle East, Southeast Asia, and Australia.

The company employed a full span launching method, where parts are prefabricated in a factory and shipped to the site for assembly, to reduce construction time and ensure safety during the process. The company also deployed two tunnel boring machines and set a new world record for the longest underground length they cut in a day.

Previously on Wednesday, the royal palace in Riyadh held a ceremony congratulating the metro's scheduled operation. Officials from Al Yamamah Palace's Royal Commission for Riyadh City, which had commissioned the project, attended the event. King Salman bin Abdulaziz Al Saud also attended the ceremony to proclaim the metro's opening.