Railways in Nigeria consist of a 3,505 km Cape gauge national railway network and 669 km of standard gauge. The Cape gauge network is in poor condition due to lack of maintenance. In 2019, the single operational standard gauge line from Abuja to Kaduna generated as much revenue as the entire Cape gauge railway network combined. The Nigerian government plans to extend the standard gauge to replace most of the Western Line, while the Eastern Line will be rehabilitated as a Cape gauge line. All trains in Nigeria are operated by the Nigerian Railway Corporation. The Nigerian Railway Corporation recorded record revenues of 2.12 billion naira (approximately €4.664 million) in the first half of 2021, an increase of 31% over the same period in 2019, which recorded the previous record revenue. At the same time, revenue from freight transport was down, with gains coming mainly from passenger transport between Lagos and Ibadan on the new standard gauge. Railway network Cape gauge 80% of the current Nigerian railways were originally built by the colonial power, Great Britain. The railways were built to the Cape gauge, the same track gauge used in most other British colonies in Africa. The country has two major Cape gauge rail lines: The Western Line connects Lagos on the Bight of Benin to Nguru in the northern state of Yobe, over a distance of . The Eastern Line connects Port Harcourt in the Southeast to Maiduguri in the northeastern state of Borno, near the border with Chad. There are also several branch lines: The Linking Line connects Kaduna on the Western Line to Kafanchan on the Eastern Line. Ifaw–Ilaro (Western Line), Minna–Baro (Western Line), Zaria–Kaura Namoda (Western Line), . Kuru–Jos (Eastern Line), Baro-Kano Railway Station (Northern Line), . The NRC network does not yet connect to the rail network of neighbouring states. However, in February 2021, construction began on a cape-gauge link from Kano to Maradi, the second-largest city in Niger, under the auspices of Portugal's Mota-Engil SGPS SA, with planned inauguration in 2023, which will be one of the first rail lines in Niger. Standard gauge lines A standard gauge network is developing. The oldest standard-gauge line is the original 217-kilometer line from Oturkpo to the Ajaokuta steel mill. An earlier standard gauge line of 51.5 kilometers operated between the Itakpe mines and the Ajaokuta steel mill. On September 29, 2020, an extension, the Warri-Itakpe Railway,