Italy’s Salini Impregilo says it has reached another milestone in the construction of Line 3 of the Riyadh Metro, with a tunnel-boring machine (TBM) arriving at the Downtown Station site.

The TBM, named Jazlah, has now excavated 4.34 kilometres of tunnel and is close to ending its 5.35km journey underground. The machine has a diameter of 10.16 metres, a length of 100 metres and a weight of 1,300 tonnes.

Salini Impregilo is leader of the Arriyadh New Mobility (ANM) consortium that was awarded the deal to deliver Line 3 in 2013. The line, which is also known as the Orange line, is more than 40km, long with about 11km underground. The tunnels will be excavated by TBMs and cut-and-cover. Once completed, Line 3 will have 22 stations.

Located near the Riyadh governor’s palace in the heart of the city, the Downtown Station will be among the most iconic, with two lines passing through it. Covering 20,000 square metres, it is being designed by Norwegian architectural firm Snohetta. Its entrance will be covered by a massive inverted cone made of stainless steel, which will provide shade for travellers and channel sunlight into the underground station.

In June this year, tunnel excavation works were completed for Line 5 (Green line) of the Riyadh Metro. It is one of the three lines awarded to the FAST consortium.

Arriyadh Development Authority awarded turnkey contracts for the metro scheme on 28 July 2013.

The six-line metro project has been divided into five major design-and-build packages, with lines 1 and 2 as one package, and the other lines each as single packages. Each package will include the supply of rolling stock.

Spanish firm FCC Construccion heads up the FAST consortium, while US firm Bechtel leads the BACS team. Italian firm Salini Impregilo is the leader of the Arriyadh New Mobility group.

The FAST consortium won lines 4, 5 and 6, which are reported to be valued at $7.82bn and the BACS team picked up lines 1 and 2 for $9.45bn, while Arriyadh New Mobility secured Line 3 for $5.21bn.