This table illustrates the underground railway systems in six major cities arranged chronologically from older to later. London is the oldest opened in 1863 meanwhile Los Angles is the latest opened in 2001. Similarly, London has the longest network of routes i.e. 394 km and Kyoto has the shortest network of 11 km. From the table, Tokyo serves the most passengers per year per 1 km of route meanwhile Washington DC serve the least passengers per year per 1 km of the route. It is observed that the greater the age of the railway system longer will be the network of routes and passengers per year. Although there is an exception to this notion as the Los Angeles system is newer than the Kyoto system but later has a shorter network of routes than others hence Los Angeles serves more passengers per year. The second exception is for systems in Paris and Tokyo, where passengers per year are much high although were built later than the London system.