Tram tracks are tagged as railway=tram. Tram-specific service=* values were never defined, and editors iD and JOSM use the railway values (crossover, siding, spur, and yard) as presets. However, tram systems rarely have spurs or sidings as seen on mainline railways. Prior to 2019, service=yard, service=siding and service=spur were in practice used interchangeably, except that tracks inside tram yards (garages, depots) were fairly consistently tagged service=yard.
In March 2019, User:Jarek Piórkowski suggests repurposing the railway values with tram-specific meanings to allow future tagging to be more consistent:
- "Normal" tracks have no service tag. These are typically tracks serving a stop where a passenger can expect to regularly board a tram. This would also include tracks that a scheduled tram servicing a route connecting these stops uses (for example end-route loops).
Tram systems can have significant differences between cities, so definition of what are "normal" tracks or what "regular" service is might differ between cities, but try to be consistent within a city/system.
- service=yard for tracks within tram storage and work areas ("yards", "garages", "depots" - where trams are parked overnight, maintained, light repairs), and for tracks leading to the yard, provided they don't have regular passenger service stops. Example in Helsinki:
- service=crossover for tracks used by double-ended trams to change direction. Only use it between two main tracks with no service tag, otherwise use service tag of the tracks that are connected.
- service=siding for tracks not described above. These will be tracks not used for normally scheduled passenger service, including diversion-only tracks, emergency, non-revenue trackage, as well as turn tracks not used in scheduled service. Example in Berlin:
See https://lists.openstreetmap.org/pipermail/tagging/2019-January/042313.html for more information including overview of tagging in January 2019.