Construction of the Riyadh Metro Red Line extension has reached a major milestone with the completion of manufacturing and factory acceptance testing of the tunnel boring machine (TBM) that will be used to excavate the underground section linking King Saud University and the Diriyah Gate development, reported the Saudi Gazette, citing senior Royal Commission for Riyadh City (RCRC) officials.

The authority said the TBM will be shipped to Riyadh to kick off the timely excavation of the 7.1-km underground section of the 8.4-km metro extension.

The Earth Pressure Balance (EPB) machine has an 11.16-m-diameter cutterhead and is 105m long. It is designed to operate in varying geological conditions while maintaining ground stability during excavation.

The Red Line extension will comprise about 7.1 km underground tunnels and 1.3 km elevated track, adding five stations to the Riyadh Metro network.

Two stations will be located at King Saud University, serving the university's main campus and Medical City, while three stations will be built in Diriyah, including one planned as an interchange with the future Line 7.

The extension is part of Riyadh's efforts to expand its public transport network and improve connectivity between the city and the Diriyah development.