French defence group Thales and construction giant Saudi Binladin Group will sign contracts on Tuesday on a SR2-billion ($533-million; Dh1.96-billion) contract to build Saudi Arabia's ambitious North-South Railway, government and company officials said. The two companies have been chosen to build signalling and security systems for the main 1,800-kilometre section of the $2.8-billion railroad, they said. The railway will link rich bauxite and phosphorus mines in the far north with planned Gulf coast processing and export facilities at Ras Al-Zour. Another 600-kilometre section to be awarded later will include a passenger line linking Riyadh with Al-Zubairah at the north end of the line. The North-South Railway project is one of three huge multi-billion dollar rail projects the government is developing. The other two are a 444-kilometre high-speed railway to link the holy cities of Mecca and Medina via Jeddah, and the Landbridge project that will link Jeddah on the Red Sea with the Gulf coast cities of Dammam and Jubail, involving some 1,100 kilometres of new track. Keep up with the latest business news from the region with the Emirates Business 24|7 daily newsletter. To subscribe to the newsletter, please click here .