Capacity constraints are forcing the expansion of the region’s oldest metro system, with its current usage rate of 3 million passengers a day expected to grow to 5 million by 2020. Cairo’s rapidly growing population is likely to hit 20 million by 2022, making significant investments in public transport necessary to keep the city running.

The three existing lines are set to be joined by a fourth, using $426m in funding from Japan Bank for International Cooperation as part of a total loan package worth $1bn.

Construction on Line 4 will begin in 2014, with the first phase due to open in 2020. In its first year of operation, the new line is expected to carry 1.35 million passengers, increasing to 2.5 million a day by 2050.

The client, the National Authority for Tunnels (NAT), is also expanding and upgrading existing tracks. In early 2013, NAT awarded France’s Systra the contract to renovate Line 1 of the Cairo metro system.

In November 2012, the European Investment Bank signed the E200m ($271m) first tranche of a E600m loan to part-fund construction of the third phase of Cairo Metro Line 3. NAT secured a E940m financing package from the EU and the French Development Agency to back the expansion plans.

Line 3 will extend from Imbaba, in the northwest of the Greater Cairo area, to Heliopolis in the northeast, and will eventually serve Cairo International airport. This will add 17.7 kilometres and 15 stations to the network. Line 3 aims to make travelling from the east of the capital to the west easier, and is also intended to reduce traffic congestion in the city.

Several companies have been prequalified for the construction contracts for the third line. Work was meant to commence this year, and be completed in 2018, but this deadline is likely to be missed.

Line 4 is to become the backbone of a proposed connection between 6 October City and the Cairo Metro, extending its reach beyond the urban Cairo environs. Under the proposals, Line 4 will meet the route of Line 2 at Giza station, where there will be a service interchange between the two lines. The likely length of this phase is 19km, with 17 stations along the route.