File:Estimated times of next trains (6337955263).jpg

English: This is one of the newer improvements in the New York City subway system: electronic status boards listing the next trains and their estimated arrival times.

New York City Subway has 24 line numbers/letters, and they run over a combination of different physical lines to make a given route. Although this station (137th Street and Broadway, City University) is only served by the No. 1 train, many stations are served by multiple lines, and in many cases, one platform may serve multiple line numbers/letters. Each platform has signs detailing which lines will stop and when (rush hour/midday/night/weekends), but even they can sometimes be confusing, and maintenance-related detours are more common than one would think.

The City University Station is the original northern terminus of the oldest subway line in the city, the Interborough Rapid Transit line opened in 1904. From here, trains ran down Broadway to Times Square, before making a hop across 42nd Street to Grand Central Terminal, then heading further downtown to terminate at City Hall. In 1918, the Times Square-Grand Central section became an isolated shuttle, as the remaining sections got separated into separate lines. Today, the City College - Times Square section runs south to South Ferry (Battery Park) and north to Van Cortlandt Park in the Bronx, with the line designation of No. 1; the Grand Central - City Hall section forms part of the No. 4, 5, and 6 lines.