Saudi Arabia plans to link its industrial city of Jubail and Dammam port to a network that connects to mining centres, the head of the company that is overseeing the railway said on Sunday.

'We are preparing the design and tendering documents and will soon tender the project. This process will take several months and the construction is expected to start at the end of this year or early next year,' Rumaih al-Rumaih, chief executive of the Saudi Railway Co (SAR), said in an emailed statement.

'The purpose of this project is to give access to factories in Jubail to use our railway network for transporting their products,' the statement said, without giving the cost of the planned 125 km Dammam-Jubail railway.

SAR has invited Saudi and global companies to pre-qualify for the Ras Azzour-Jubail link and the deadline for tendering is July 30, according to another emailed statement.

SAR is managing the kingdom's longest railway project, the 2,400km North/South railway, and is financed by the state-run Public Investment Fund (PIF).

In May, it started initial operations on a 1,392 km mineral line, linking phosphate mines at al-Jalamaid and a bauxite mine at Az-Zabirah to processing facilities at the industrial hub of Ras Azzour on the Gulf coast.

Saudi Arabia has two other railway projects and aims to link its lines to other Gulf countries in future. The kingdom is spending billions of dollars boosting its infrastructure.

The Haramain Railway in the west of the country will connect the spiritual heart of Islam, Makkkah, and its second-most sacred city Medina, to the kingdom's commercial hub in Jeddah on the Red Sea coast.

The railway is also expected to connect to King Abdullah Economic City, an ultra-modern city and business hub.

The kingdom is also studying the construction of a Landbridge railway line to link its eastern and western coasts.-Reuters