Riyadh Metro: Colossal engines work overtime

Construction on the multibillion-riyal Riyadh Metro is well under way with several giant drilling machines working overtime to ensure that underground tunnels for the project are completed on schedule.

The Arriyadh Development Authority (ADA) conducted a tour of the operations for the media on Wednesday, 25 meters underground on the 1.6 km-long green line running along King Abdulaziz Road.

Journalists were able to see a tunnel boring machine in action. They were accompanied by Al-Waleed bin Abdulrahman Al-Ekresh, director general of the ADA for development and integrated utilities, who briefed the media on the operation covering the two parts of the project — the metro and the public buses.

The machines used to carve out the tunnels also line the walls with concrete as they move along, and include safety and air-conditioning systems and the automatic processing lines that carry away waste material.
There are seven gigantic machines, each between 90 and 120 meters, and able to dig away daily 50 truckloads of earth. Each machine weighs about 2,000 tons, the equivalent of four 747 jets with full cargo.