He says 21 tunnel boring machines are currently working on the metro. "I am very proud to announce that Qatar Rail has achieved a quantum leap in executing its tunnelling works, breaking the world record for the largest number of tunnel boring machines operating at the same time under one city," says Al-Subaie.

The first phase of the metro comprises the construction of three lines (Red, Gold, and Green), out of the four lines planned, and 37 stations. Al-Subaie says the project is on schedule with the three lines forecast to open by late 2019.

Contracts worth Riyals 60bn ($US 16.5bn) have been awarded to nine joint ventures. Pre-qualification for the mechanical and electrical, as well as the architectural works will be closing shortly, while prequalification for the operation and facility management is progressing with the target to float tenders by the middle of 2016.