From OpenStreetMap Wiki
|passenger = urban|
|Used to mark a railway route with the type of passenger traffic as urban.|
|Used on these elements|
|Tools for this tag|
- City center services mainly underground.
- In North America, this tag is often appropriate for urban railway=light_rail and sometimes railway=tram systems, serving a single metropolitan area (not linking larger, multiple county areas like passenger=suburban services). While some railway=light_rail systems do have underground segments, many are above ground in a dedicated right-of-way, though sometimes in denser urban areas they are street-running trams. Examples: San Diego Trolley, San Francisco Muni Metro, Calgary CTrain, Mexico City Xochimilco Light Rail and Newark Light Rail.