Saudi Railways Organization, or SRO, said Wednesday it awarded Saudi Bin Laden Group and Saudi Oger contracts worth 9.4 billion Saudi riyals ($2.5 billion) to build four stations as part of a 450-kilometer railway that will link the holy cities of Mecca and Medina to Jeddah.

The four stations are in Mecca, Jeddah, Medina and King Abdullah Economic City in Rabigh, SRO said in a statement.

In July, SRO said it has received two bids from Al Rajhi group, including Saudi builder Al-Rajhi, Alstom and state railway SNCF, and the Spanish-Saudi consortium Al Shoula group for the second stage of the rail. The $1.4 billion in contracts will involve laying tracks, installing signals, and communications, operation and maintenance.

Upon completion of construction, the bidder is required to operate and maintain the entire infrastructure for 12 years.

A group of advisers and consultants including Scott Wilson Group PLC (SWG.LN) were appointed to study the technical proposals and look into the submitted financial bids.

The rail line will connect Mecca with Medina via Jeddah and King Abdullah Economic City. This will also connect to the Landbridge and the north-south line, linking Saudi population centers with industrial zones and the new economic cities.

The project aims to ease the congestion on the road linking the two cities during the Muslim haj and umrah pilgrimages and reduce the duration of the road trip.

The railway is expected to carry at least 3 million people a year.