Qatar Rail has formally announced the winners of contracts worth a combined $8.2bn for the first phase of the Doha Metro.
The organisation said that the award of the four phase one contracts - Red Line North (RLN), Red Line South (RLS), the Green Line (GRN) and the Major Stations (MS) marks a 'key milestone' in the project's development.
As previously reported, the Red Line North contract has gone to a consortium led by Italian firm Impregilo alongside South Korea's SK Engineering Construction Co and Galfar Al Misnad Engineering Contracting.
The Red Line South contract has gone to a consortium led by QDVC including GS Engineering & Construction and Al-Darwish Engineering.
The Green Line project has been awarded to the consortium that is already carrying out the enabling works - Austrian contractor Porr, Qatar's HBK and and Saudi Binladin Group.
Meanwhile, the Major Stations contract for the Msheireb and Education City stations has been awarded to a consortia led by Samsung CT Corporation with Spain's Obrascon Huarte Lain S.A. (OHL) and Qatar Building Company.
In a statement, the company said that it planned to start construction by the end of the year, so that work will complete on schedule by 2019.
"This is a big step towards putting Qatar Rail into operations and moving forward with the work ahead of us as we build the future of Qatar, " it added.
"Qatar Rail is committed to achieving the highest international standards in creating this signature project in national development that will become an international legacy for Qatar for generations to come'.
It added that there were high levels of competition for the work, which meant the bidding process was competitive.
The Red Line North contract covers the design and construction of 13km of twin-bored tunnels and seven underground stations between Msheireb and Doha Golf Course via West Bay. Some four tunnel boring machines will be used on the contract, with the tunnels being dug at ah average of 20m below ground.
Red Line South will see six underground stations being built between Msheireb and the new Sheikh Hamad International Airport. It also includes the main depot and maintenance facilities. This will see five tunnel boring machines used to carve out a 13.8km twin bored tunnel. Although the tunnel will have an average depth of 25m, it will reach 50m below ground at its deepest point.
Meanwhile, the Green Line contract will link from Msheireb to the Al Rayyan Stadium. It will have eight stations and its 16.6km-long twin-bored tunnel will be built at an average of 20 metres.
The Major Stations contract is for the Msheireb station in the middle of the new Downtown Doha development which will link all of the network's lines. It will involve excavating 42m below ground. THe Education City station will link to Qatar's long-distance rail network, which is being built in three phases.
'All the technical and commercial committees worked in the past months diligently with full transparency to ensure the awarding of contracts for the best alliances technically and commercially'," Qatar Rail said.
"Although the tunnelling and the construction of the stations are being executed for the first time in Qatar, Qatar Rail has succeeded in engaging Qatari contracting companies in all consortiums of the awarded contracts."