README for “Railroad Bridges” dataset. U.S. Department of Transportation (DOT), Federal Railroad Administration (FRA); U.S. Department of Transportation (USDOT), Bureau of Transportation Statistics (BTS) [distributor] 2025-05-29 ---------------------------------------------------------------- LINKS TO DATASET ---------------------------------------------------------------- A. Dataset archive link: https://doi.org/10.21949/1520834 B. NTAD catalog dataset link (Current Year): https://doi.org/10.21949/1528165 ---------------------------------------------------------------- SUMMARY OF DATASET ---------------------------------------------------------------- The Railroad Bridges dataset is from the Federal Railroad Administration (FRA), and is part of the U.S. Department of Transportation (USDOT)/Bureau of Transportation Statistics’s (BTS's) National Transportation Atlas Database (NTAD). A railroad bridge is defined as “Railroad bridge means any structure with a deck, regardless of length, which supports one or more railroad tracks, or any other undergrade structure with an individual span length of 10 feet or more located at such a depth that it is affected by live loads.” based on the Code of Federal Regulations (49 CFR Part 237). The FRA does not have a mandate to inspect railroad bridges: these inspections are required by the owner of the track. The FRA will use this railroad bridge dataset to determine the number of bridges per railroad, state, etc. and will assist in determining priority field activities. ---------------------------------------------------------------- TABLE OF CONTENTS ---------------------------------------------------------------- A. General Information B. Sharing/Access & Policies Information C. Data and Related File Overview D. Methodological Information E. Data-Specific Information for: Railroad Bridges [datasets] F. Update Log ---------------------------------------------------------------- A. GENERAL INFORMATION ---------------------------------------------------------------- 0. Title of Dataset: Railroad Bridges [dataset] 1. Description of Dataset: The Railroad Bridges dataset is from the Federal Railroad Administration (FRA), and is part of the U.S. Department of Transportation (USDOT)/Bureau of Transportation Statistics’ (BTS's) National Transportation Atlas Database (NTAD). A railroad bridge is defined as “Railroad bridge means any structure with a deck, regardless of length, which supports one or more railroad tracks, or any other undergrade structure with an individual span length of 10 feet or more located at such a depth that it is affected by live loads.” based on the Code of Federal Regulations (49 CFR Part 237). The FRA does not have a mandate to inspect railroad bridges: these inspections are required by the owner of the track. The FRA will use this railroad bridge dataset to determine the number of bridges per railroad, state, etc. and will assist in determining priority field activities. 2. Dataset archive link: https://doi.org/10.21949/1520834 3. Authorship Information: Principal Data Creator or Data Manager Contact Information Institution: U.S. Department of Transportation (DOT), Federal Railroad Administration (FRA) Address: 1200 New Jersey Ave SE, Washington D.C. 20590 Contact: frapa@dot.gov Data Distributor Contact Information Name: National Transportation Atlas Database (NTAD) Institution: U.S. Department of Transportation (USDOT), Bureau of Transportation Statistics (BTS), Office of Spatial Analysis and Visualization (OSAV) Address: 1200 New Jersey Ave. SE, Washington D.C. 20590 Email: ntad@dot.gov 4. Date of data collection and update interval: This dataset is updated as needed. 5. Geographic location of data collection: United States of America 6. Information about funding sources that supported the collection of the data: Federal Railroad Administration (FRA), U.S. Department of Transportation (DOT) ---------------------------------------------------------------- B. SHARING/ACCESS & POLICIES INFORMATION ---------------------------------------------------------------- 0. Recommended citation for the data: U.S. Department of Transportation (DOT), Federal Railroad Administration (FRA), U.S. Department of Transportation, Bureau of Transportation Statistics (BTS) [distributor]. Railroad Bridges [datasets]. https://doi.org/10.21949/1520834 1. Licenses/restrictions placed on the data: These data are in the Public Domain. 2. Was data derived from another source?: Yes. The dataset was generated from the FRA grade Bridges inventory which populates FRA GIS grade Bridges layer monthly. 3.This document was created to meet the requirements enumerated in the U.S. Department of Transportation's 'Plan to Increase Public Access to the Results of Federally-Funded Scientific Research' Version 1.1 << https://doi.org/10.21949/1520559 >> and guidelines suggested by the DOT Public Access website << https://doi.org/10.21949/1503647 >>, in effect and current as of December 03, 2020. ---------------------------------------------------------------- C. DATA & RELATED FILE OVERVIEW ---------------------------------------------------------------- 1. File List for the Railroad Bridges dataset A. Filename: Railroad_Bridges_NTAD2010_2013.zip and Railroad_Bridge_NTAD2022_Present.zip Short description: Compressed file folders containing the geospatial data for Railroad Bridges dataset. File folders are classified by NTAD publication year and data vintage year or date respectively. B. Filename: bts_NTAD_Railroad_Bridges_DMP_20250529.pdf Short description: A PDF file containing the Data Management Plan that was created for current and future management of the data and associated files. C. Filename: bts_NTAD_Railroad_Bridges_README_20250529.txt Short description: The README.txt file that includes human-readable information about the data, variable definitions, contact information, and other contextual information. The file you are reading now. 2. File List for the Railroad_Bridges_NTAD2010_2013.zip and Railroad_Bridge_NTAD2022_Present.zip collections. A. Filename: NTADXXXX_SHP_Final_Railroad_Bridges_2010.zip or NTAD2022_GDB_Final_Railroad_Bridges_2022_10_14.zip Short description: Compressed file folders containing the geospatial data for Railroad Bridges dataset. File folders are classified by NTAD publication year and data vintage year respectively. 3a. File List for the NTADXXXX_SHP_Final_Railroad_Bridges_2010*.zip collection. A. Filename: rr_bridges.shp Short description: A shapefile containing the geospatial data for Railroad Bridges dataset. This includes associated files with extensions .prj, .dbf, .sbn, .sbx, .shx. B. Filename: bb_bridges.txt, rr_bridges.htm, and rr_bridges.shp.xml Short description: Text files containing key metadata and documentation information such as methodology, procedures, data dictionary, etc. 3b. File List for the NTAD2022_GDB_Final_Railroad_Bridges_2022_10_14.zip collection A. Filename: NTAD2022_GDB_Final_Railroad_Bridges_2022_10_14.gdb.zip Short description: A file geodatabase containing the geospatial data for Railroad Bridges dataset. Geodatabase (GDB) folders contain all the necessary components to view and otherwise interact with their data. ---------------------------------------------------------------- D. METHODOLOGICAL INFORMATION ---------------------------------------------------------------- 1. Description of methods used for collection/generation of data: Business Rules for Primary Conflation 1. Grade Crossing related to abandoned railroad a. Conflate Grade Crossing point to the intersection of abandoned railroad and road, then flag it as “BridgeRelatedToAbandoned” 2. Grade crossing has same street name as Tiger and rail owner as FRA railroad a. Capture Tiger street name as primary and leave secondary street name blank. Capture FRA rail owner as primary and leave secondary rail owner blank. No flag needed. 3. Grade crossing has same rail owner but different street name than Tiger road a. Conflate grade crossing to the intersection point, capture the Tiger road name as primary and grade crossing street name as secondary. Flag this bridge as “StreetNameUnmacthed”. 4. Grade crossing has street name, but Tiger road source does not a. Conflate grade crossing to the intersection point. Leave primary street name blank and capture grade crossing street name as secondary. Flag the bridge as “StreetNameUnmatched”. 5. Grade crossing has same street name but different railroad owner than FRA railroad a. Conflate grade crossing to the intersection point, capture the FRA railroad owner as primary owner and grade crossing rail owner as secondary. Capture the Tiger road street name as primary, leave secondary street name blank. Flag this bridge as “RailOwnerUnmatched”. 6. Grade crossing has railroad owner, but FRA railroad segment does not a. Conflate grade crossing to the intersection. Leave primary rail owner blank and capture grade crossing rail owner as secondary. Flag the bridge as “RailroadNoOwner”. 7. Grade crossing has no street name a. In urban area, if only one intersection in buffer of 200 meters (500 meters for rural areas), rail owner is matched, and the bridge can be observed on the image, and then conflate grade crossing bridge to the intersection point, capture the Tiger street name as primary and leave secondary street name blank. Flag this bridge as “GXingNoStreet”. 8. No Grade Crossing found a. Consider this as a new bridge, capture railroad owner and street name from its corresponding FRA railroad and Tiger road. Flag it as “NoGXing” 9. Census Tiger road missing a road segment a. Visually identify the bridge location based on Bing or Google imagery, capture street name from Tiger or Google Map and flag the cases as “NoStreet”. 10. FRA network is missing railroad segment4 a. Visually identify target based on imagery. Flag the case as “NoRailroad” 11. An overpass railroad bridge over multiple Tiger roads a. If street names are the same, group intersection points and use the group center as the bridge location. Flag this case as “OverMulitpleRoads” b. If street names are different, multiple bridges will be generated, with each one corresponding to one street. Flag it as “OverMulitpleRoadsUnmatched” 12. Multiple overpass bridges over a Tiger road a. If same rail owner and not structurally separated, group intersection points and use the group center as the bridge location. Flag it as “MultipleRailroadOver”. b. If same railownerbut structurally separated, multiple bridges are generated. Flag it as “MultipleRailroadOver”. c. If different rail owners, multiple bridges are generated. Flag it as “MultipleRailroadUnmatchedOver” 13. An overpass road bridge over multiple railroads a. If same rail owners, group intersection points and use the group center as the bridge location. Flag it as “MultipleRailroadUnder” b. If different rail owners, multiple bridges are generated. Flag it as “MultipleRailroadUnmatchedUnder” 14. No Grade Crossing Bridge source, NBI or ATIP bridge exists a. Generate a new bridge and capture FRA rail owner as primary. If ATIP is available and has different rail owner, capture rail owner as secondary. Capture bridge type, design type, length from NBI if available. Otherwise visually identify the bridge type. 15. Water bridge has different railroad owner than railroad a. Conflate the water bridge to the intersection point. Capture FRA rail owner as primary and water bridge rail owner as secondary. Flag this bridge as “WaterBridgeUnmatched” 16. Missing water bridge source a. Consider this intersection as a new bridge. Capture FRA rail owner as primary and waterway name. If ATIP available and has different rail owner, capture its rail owner as secondary. Flag this intersection point as “NoWaterBridge” 17. Waterway Target related to abandoned railroad a. Conflate water bridge point to the intersection of abandoned railroad and waterway, then flag it as “WaterBridgeRelatedToAbandoned” 18. NBI as source for bridge type, design type, and bridge length a. If NBI data is found within the buffer of 20 meters, use its STRUCTURE_LEN_MT_049, STRUCTURE_TYPE_043B, STRUCTURE_KIND_043A as the bridge length, bridge type, and design type respectively. Flag this intersection point as “NBI” 19. No NBI a. Visually identify the bridge type, design type, and manually measure bridge length based on imagery and flag the cases as “NoNBI”. 20. Overlapping intersection points due to overlapping Tiger roads a. Only one bridge will be generated. Capture the street name as the primary street name from one Tiger street segment 21. Overlapping Grade Crossings a. Keep the one with the matched rail owner and street name b. If no matched found, follow below rules: non-closed>closed, only rail owner matched >neither matched, public>private, above/below> at, latest revision date or last updated. c. 3. If key fields are the same, just pick up the either one 22. Abandoned bridge a. Visually identify the abandoned bridge based on Bing or Google imagery and flag the cases as “FRA Abandoned”. 23. Multiple railroads over a waterway a. If same rail owner and not structurally separated, group intersection points and use the group center as the bridge location. Flag it as “MultipleRailroadOver”. b. If same rail owner but structurally separated, multiple bridges are generated. Flag it as “MultipleRailroadOver”. c. If different rail owners, multiple bridges are generated. Flag it as “MultipleRailroadUnmatchedOver” 24. Bridge Attribute: City Name (No Data Source) a. Developed a batch process tool to get city name for all the bridges 25. Bridge Attribute: Num_Tracks and SUBDIV a. If a bridge is related to the multiple railroad line segments, the Num of Tracks for bridge will be “Multiple”. For example, if a bridge point is the intersection of the one road and the multiple railroad line segment with the same railroad owner, the Num of Tracks should be “Multiple”. b. If a bridge is related to the single railroad line segment, but the attribute value of TRACKS for the railroad line segment is more than 1, the Num of Tracks should be still populated as “Multiple”, Otherwise, it will be populated as “One” c. Get SUBDIV from main track (NET=“M”). If no main tracks found, the value of SUBDIV is set to be “Unknown” 26. Bridge Attribute: Attribute: Rail_MilePost a. ~ 50% of bridges do not have rail milepost; If no corresponding Milepost found, the value of Rail Milepost set to be “Unknown” 27. Follow the following rules to populate the column “NAME” and the column “SECONDARY_STREETNAMES” a. If one of the overlapping street names in TIGER matches the street name on Grade Crossing database, that street name will go to the column “NAME”. b. If no road name matches the street name in the Grade Crossing database, check the tiger MTFCC code, the road name with the highest function code will go to the column “NAME. c. If the function codes for the streets are the same, check the tiger RTTYP, the road name with the highest type code ("U“> "S“>"I“> “C“> “M“> "O") will go to the column “NAME. d. If the function codes and road type are the same, check if the street name includes a number such as “1STstreet”, “Rte80” or “HWY 9”. The road name which contains a number will go to the column “NAME”. e. If none of the street names contain a number, then either street name will go to the column “NAME”. f. The rest of the street names will go to the column “SECONDARY_STREETNAMES”. 28. Overlapping intersection points due to overlapping/crossing FRA Railroads a. If RROWNER are different, multiple bridges will be generated at the same location, with one bridge for one RROWNER Business Rules for Processing Rail over Rail Business Rules for Processing HIFLD/NGA Railroad Bridges 1. No Bridge found around NGA point a. Definitions: • No railroad observed or • Railroad present but no FRA bridge observed b. Solution: • NGA Bridge Point will not be conflated to FRA bridge 2. Stream bridge found around NGA point a. Definitions: • Railroad is observed, stream can be observed underneath railroad, and bridge or arch bridge can be observed • Its width is greater than10 feet b. Solution: • NGA Bridge Point will be conflated to FRA bridge; the bridge will be snapped to railroad. 3. FRA bridge identified near NGA point a. Definitions: • Railroad observed, but a FRA bridge already identified nearby b. Solution: • NGA Bridge Point will not be conflated to FRA bridge 4. Bridge present near NGA point a. Definitions: • Railroad observed, a bridge found at NGA point b. Solution: • NGA Point will be conflated to FRA bridge and its location will be moved to be on the FRA railroad 5. Business Rule 5: Cannot clearly see a bridge near NGA point a. Definitions: • Railroad present, cannot clearly see if there is a bridge or not due to poor image quality or blocked by tree b. Solution: • NGA Bridge Point will not be conflated to FRA bridge 2. Instrument- or software-specific information needed to interpret the data: The data and documentation files can be opened with Esri ArcMap and any GIS software package. ---------------------------------------------------------------- E. DATA-SPECIFIC INFORMATION ---------------------------------------------------------------- 1. Railroad Bridges data table This dataset is updated as needed. Dataset Manager is contacted to verify changes to data resulting in NTAD update. The metadata is updated in the same manner. For the most recent data, please visit the NTAD catalog at https://doi.org/10.21949/1528165 A. Number of variables (columns): The data dictionary found in (PDF documentation) provides definitions for the variables B. Data Dictionary/Variable List: Because of the large number of variables, please refer to the Data Dictionary found within the file Railroad_Bridges.txt for names, definitions, and formats of variables. C. Missing data codes: None ---------------------------------------------------------------- F. UPDATE LOG ---------------------------------------------------------------- This bts_Railroad_Bridges_20250529_README.txt file was originally created on 2021-02-16 by Dominic Menegus, Geographer, dominic.menegus@dot.gov [Note changes or update to the readme.txt file, e.g.:] 2021-02-16: Original file created 2025-05-29: Revised document, including data descriptions and file organization.