The map below shows the approximate current location of trains within the Metrorail system (automatically updated every 60 seconds). Train markers have a letter indicating the station at the end of the line in the direction which the train is headed (for example, on the orange line ‘V’ indicates a train headed west, in the direction of Vienna). Clicking on a station will bring up the estimated train arrival times for that station.
If you are new to the Washington metro system, you can learn more by visiting our general metrorail page.
There has been some interest in how this application actually works. The data, provided by WMATA’s developer api, gives the same information found on the information boards in metro stations. After finding the approximate time distance between stations, the application simply interpolates latitudes and longitudes between those stations (with minute granularity) to determine an estimated location. Since information on the information boards is not always complete, and provides information at the station level (rather than at the train level) it is possible for the algorithm to temporally miss trains, or double count trains (though we try to avoid doing this).
A full-window version is avaliable here.