Central line (London Underground) and Great Eastern Railway buildings east of , from when the line to Epping was a rural branch line. In terms of total passengers, the Central line is the busiest on the Underground. In 2011/12 over 260 million passenger journeys were recorded on the line. It currently operates the second-most frequent service on the network, with 34 trains per hour (tph) operating for half-an-hour in the westbound direction during the morning peak, and between 27 and 30 tph during the rest of the peak. This makes the Central line the busiest and most intensively-used railway line in the United Kingdom:
Seoul Subway Line 5 underground railway tunnels of any kind constructed. Today it is the third longest continuous underground subway tunnel in the world, just behind Guangzhou Metro Line 3 and Beijing Subway Line 10. The line was built 1990~1996 and is an important east-west link connecting Gimpo Airport, the Yeouido business area, downtown Seoul, and the Gangdong residential districts. In 1996 Line 5 was implemented with Automatic train operation. However, it was deemed that a driver would be necessary in case of a breakdown of the automation system, therefore each subway train has one driver on board. It was the world's longest underground