The 22-station line will be designed for 120km/h operation and will cross 10 of Nigeria's 36 states, including the oil producing Niger Delta region.

CRCC said the deal was preceded by a framework contract between Nigeria's Ministry of Transport and the company's China Civil Engineering Construction Corporation (CCECC) subsidiary, which was signed in May. CRCC will export $US 4bn worth of construction machinery, trains and steel products to Nigeria to build the double-track standard-gauge line.

The contractor has declined to provide any details of construction timescales or financing, although many of its previous projects outside China have been largely financed by the Export-Import Bank of China.

CCECC is currently involved in the construction of the Lagos Rail Mass Transit network and of the 186km Abuja – Kaduna standard-gauge line.