page_title: Reporting mark
section_title: North America
hierarchical_section_title: Reporting mark / Standard practices / North America
caption_attribution_description: English: RTDX 4001 reporting mark sign seen from RTDX 4004 cab
context_page_description: A reporting mark is an alphabetic code of two to four 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 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.
context_section_description: The Association of American Railroads (AAR) assigns marks to all carriers, under authority granted by the U.S. Surface Transportation Board, Transport Canada, and Mexican Government.
  Under current practice, the first letter must match the initial letter of the railroad name. As it also acts as a Standard Carrier Alpha Code, the reporting mark cannot conflict with codes in use by other nonrail carriers.
  Marks ending with the letter "X" are assigned to companies or individuals who own railcars, but are not operating railroads; for example, the TTX Company (formerly Trailer Train Company) is named for its original reporting mark of TTX. In another example, the reporting mark for state-funded Amtrak services in California is CDTX (whereas the usual Amtrak mark is AMTK) because the state transportation agency (Caltrans) owns the equipment used in these services. This may also apply to commuter rail, for example Metrolink in Southern California uses the reporting mark SCAX because the equipment is owned by the Southern California Regional Rail Authority—which owns the Metrolink system—even though it is operated by Amtrak. This is why the reporting mark for CSX Transportation, which is an operating railroad, is CSXT instead of CSX. Private (non-common carrier) freight car owners in Mexico were issued, up until around 1990, reporting marks ending in two X's, possibly to signify that their cars followed different regulations (such as bans on friction bearing trucks) than their American counterparts and so their viability for interchange service was impaired. This often resulted in five-letter reporting marks, an option not otherwise allowed by the AAR.
  Companies owning trailers used in trailer-on-flatcar service are assigned marks ending with the letter "Z", and the National Motor Freight Traffic Association, which maintains the list of Standard Carrier Alpha Codes, assigns marks ending in U to owners of intermodal containers. The standard ISO 6346 covers identifiers for intermodal containers.
  When the owner of a reporting mark is taken over by another company, the old mark becomes the property of the new company. For example, when the Union Pacific Railroad (mark UP) acquired the Chicago and North Western Railway (mark CNW) in the 1990s, it retained the CNW mark rather than immediately repaint all acquired equipment. Some companies own several marks that are used to identify different classes of cars, such as boxcars or gondolas.  If the acquiring company discontinues the name or mark of the acquired company, the discontinued mark is referred to as a "fallen flag" railway. Occasionally, long-disused marks are suddenly revived by the companies which now own them. For example, in recent years, the Union Pacific Railroad has begun to use the mark CMO on newly built covered hoppers, gondolas and five-bay coal hoppers. CMO originally belonged to a predecessor of the CNW, which passed it on to them, from which the UP inherited it. Similarly, during the breakup of Conrail, the long-retired marks of the Pennsylvania Railroad (PRR) and New York Central Railroad (NYC) were temporarily brought back and applied to much of Conrail's fleet to signify which cars and locomotives were to go to CSX (all cars labeled NYC) and which to Norfolk Southern (all cars labeled PRR). Some of these cars still retain their temporary NYC marks.
caption: A temporary window sign with RTDX markings
exif: {"Image ImageWidth": "1536", "Image ImageLength": "2560", "Image Make": "SAMSUNG", "Image Model": "SM-S765C", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "S765CUDUANC1", "Image DateTime": "2014:12:06 13:58:18", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "274", "GPS GPSVersionID": "[2, 2, 0, 0]", "Image GPSInfo": "690", "Image ExposureMode": "Auto Exposure", "Image WhiteBalance": "Auto", "Image FocalLengthIn35mmFilm": "31", "Image SceneCaptureType": "Standard", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail Orientation": "Rotated 90 CW", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "814", "Thumbnail JPEGInterchangeFormatLength": "18210", "EXIF ExposureTime": "1/40", "EXIF FNumber": "13/5", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "100", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2014:12:06 13:58:18", "EXIF DateTimeDigitized": "2014:12:06 13:58:18", "EXIF ComponentsConfiguration": "YCbCr", "EXIF MaxApertureValue": "69/25", "EXIF MeteringMode": "CenterWeightedAverage", "EXIF LightSource": "Unknown", "EXIF Flash": "Flash did not fire", "EXIF FocalLength": "343/100", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "1536", "EXIF ExifImageLength": "2560", "EXIF SensingMethod": "One-chip color area", "EXIF SceneType": "Directly Photographed"}