|usage = branch|
|Specifies that a railway is a branch line, with less traffic and lower speed than main lines, often single tracked, not electrified, constructed to lower specifications than a main line. May connect a place to a mainline or serve to connect mainlines.|
|Used on these elements|
|Status: de facto|
|Tools for this tag|
The tag usage=branch is used together with railway=* to map a branch line: a railway with less traffic and lower speed than main lines, often single tracked and/or not electrified, may be constructed to lower specifications than main line. May connect a place to a mainline or serve to connect mainlines, typically a few dozen miles in length.
The distinction between main and branch line in general should be straightforward, but may be vague in certain circumstances; for example, if the branch line is very long. Some generic criteria are described in the table, below, but one should consider each case individually. Often, branch lines are described as such in the official name, however, sometimes rail is named "XYZ Main Line" even though it is more appropriately tagged usage=branch.
This is in principle independent of the kind of railway, but it is most often used with railway=rail and railway=narrow_gauge.
|A track is either tagged with usage=branch or with service=*, not with both.|
Inside a railway station area, use usage=* only for the main tracks (not for siding, yard tracks etc.). That also applies for crossover or overtaking tracks outside of the railway stations.
Other values of usage=*:
|usage=main||Main line, presumably heavy traffic, often double tracked and/or electrified, may be high speed.|
|usage=industrial||Tracks in private use that serve only freight transport inside ports, industrial complexes or mining areas, and for connecting these to the public network|
|usage=military||Tracks for military use, mainly on military areas, munitions storage areas or connections to the public railroad network.|
|usage=test||Tracks used for testing of new vehicles or new rail transport technologies.|
|usage=tourism||Tracks for tourists, around museums, historic or "heritage" trains, often only on weekends and holidays and/or seasonally, most preserved railways (railway=preserved and railway:preserved=yes)|