|The reporting marks of the operator(s) of a given feature of a North American railway|
|Used on these elements|
|Status: in use|
|Tools for this tag|
This is a regional tag used for railway-related features in North America, including Canada, Mexico, and the United States. For other OpenRailwayMap tags and usages particular to North America, see OpenRailwayMap/Tagging in North America.
This tag should contain the reporting marks of one or more companies who operate a railway-related feature. The set of reporting marks in this tag should match the set of names in operator=* in both order and quantity (i.e. primary operator first, trackage rights holders after), with multiple values separated by a semicolon (;). (This formatting is still a subject of active discussion, see talk.) It may be helpful to think of reporting_marks=* as a kind of short form (no longer than "ABCD") of operator=* values, similar to a "company code."
The reporting marks system is shared and coordinated between the three countries of the region, which interchange a considerable volume of rail traffic with each other. While reporting marks are officially intended to be an identifier for ownership of rolling stock or equipment, they are in widespread, common use as short form identifiers (short names) for railroad companies, including widespread use for this purpose in official government documentation and databases (including geographic / GIS databases) and by the railroads themselves.
From Wikipedia: "reporting mark is an alphabetic code of two to four (capital) letters used to identify owners or lessees of rolling stock and other equipment used on certain rail transport networks. In North America the mark, which consists of an alphabetic code of one to four (capital) letters, is stenciled on each piece of equipment, along with a one- to six-digit number. This information is used to uniquely identify every such rail car or locomotive, thus allowing it to be tracked by the railroad they are traveling over, which shares the information with other railroads and customers." To be clear, only the two-to-four capital letter alphabetic code is what OSM includes as the value of this key, not the acompanying one- to six-digit number. And as OSM maps rail features, not railcars, by using this tag to mean "the one or more companies who operate a railway-related feature," it will only usefully be applied to rail features that OSM maps, primarily but not exclusively railway=rail. So, reporting_marks=* can be used on many other "railway-related features" in OSM, such as polygons tagged landuse=railway or nodes tagged railway=yard.
A single railroad may own more than one reporting mark, and in fact most large railroads do own more than one reporting mark, due to an extensive history of railway mergers. In fact, the example image here shows just such a situation. However, a single mark is always considered to be the primary mark for each railroad, and only this primary mark should be entered in reporting_marks=* for a particular rail company. For almost all railroads in North America, the Wikipedia article on the railroad is generally a reliable source of the correct primary reporting mark.
This tag may be in the process of being superceded by the less-North American-specific and more international / used-globally-within-OSM/ORM tag operator:short=*. This wiki (and a new one for that tag) will reflect that if / as it occurs.
Historically, both reporting_marks=* and reporting_mark=* have been used within North America for this purpose. After discussion, we agreed to consolidate to reporting_marks=* for this purpose. Consolidating to a single key was desired for reliability going forward, and as it will be common for this field to contain multiple values, the plural form makes sense. If you encounter reporting_mark=* while editing, please correct the key name to match this current guidance.