The list of urban rail systems in Japan lists urban rail transit systems in Japan, organized by metropolitan area (都市圏), including number of stations, length (km), and average daily and annual ridership volume.
Data is broken down at the line level, then rolled up for each specific railway operator.
Some station pairs are officially considered interchanges by their respective railway operators despite having different names (e.g., Tameike-Sannō and Kokkai-gijidō-mae on the Tokyo Metro and Tenjin and Tenjin-Minami on the Fukuoka City Subway).
Similarly, tabulations for the larger tram systems with a high degree of interlining, such as Hiroshima Electric Railway, also consider only unique segments, and sections where multiple routes overlap are only counted once.
Examples include the various quadruple-track sections of East Japan Railway Company (JR East) that provide segregated local and rapid services (e.g., Chūō Rapid Line vs. Chūō-Sōbu Line).
For example, trackage on the Toei Asakusa Line is not counted under Keikyu Corporation, Keisei Electric Railway, or the Hokusō Railway, despite the fact that all three operate their trains on the Asakusa Line.
In cases where data for only one of the two is available, care has been taken to not extrapolate the passenger volume to obtain the other, as there is a potential margin of error when attempting to derive average daily ridership from annual ridership (which is usually rounded to the nearest thousand passengers) and natural disasters or other unforeseen situations may force some operators to shut down for extended periods of time, as happened with the Sendai Subway in the days following the 2011 Tōhoku earthquake and tsunami.