Kaijo Loop Line

The Kaijo Loop Line is a railway loop line in Kaijo, Teiko, operated by the Teiko National Railways Corporation. It is one of Kaijo's busiest and most important lines, connecting most of Kaijo's major stations and urban centres, including Aoi, the Amabuki area, Shinizaka, Hakata, Fukuoka, Sakai and Shirofuku, with all but two of its 29 stations connecting to other railway or underground (subway) lines.

Outline
This loop line consists of two tracks around the heart of Kaijo Metropolis. Most trains consist of 8 carriages, with distinctive blue colour with white TNRC graphics on the front, rear and sides. The train schedule varies, but on average, two trains leave Hakata Station every 2.5 minutes during peak hours, in opposite directions. A complete loop takes around 65 to 72 minutes. Each train stops at all stations.

Ridership and overcrowding
The ridership of the Kaijo Loop Line in 2017 is 1,365,921 passengers making it the busiest rail line in the country. As the main line connecting Kaijo's major commuter hubs and commercial areas, the line was very heavily used. Sections of the line were running over 250% capacity in the 1990s and remained above 200% for most of the 2000s. In 2017, efforts to curb overuse by laying parallel lines reduced overcrowding by nearly 80%. The busiest section of the line (Fuma to Fukuoka) runs at 140% capacity.

History
The predecessor of the present-day Kaijo Loop Line was opened on 22 August 1881 by the Teiko Railway Company, operating between Fukuoka Station in the west and Hakata Station in the east. The western portion of the line between Shirofuku and Sakai was opened on 18 October 1901, and both lines were merged to become the Tohto Line on 11 September 1908. The line were electrified in 1912, in the same year the Tohto Line was double-tracked. The loop was completed in 1926 with the construction of a double track line from Hakata to Shorofuku.