Preserving Marks During Railroad Abandonment
Many geodetic control survey marks were established along railway corridors. As rails are abandoned, NGS and its partners are afforded an opportunity to preserve geodetic control marks. See Code of Federal Regulation (CFR) Title 49, Part 1105, Subpart 7.
Guidance
Geodetic survey marks can often be preserved or reset with advanced planning. Any disturbed or destroyed marks should be reported to NGS.
- NGS Data Explorer: locate marks in your area of interest.
- Mark Recovery Submission Form: update the condition of the mark, including information about a mark’s disturbance or destruction.
- Bench Mark Reset Guidelines: preserve elevation data even if a mark is going to be disturbed or destroyed.
Learn More
Preserving Marks
Significant resources were invested to create an extensive geodetic network across the United States by establishing precise coordinates at physical survey marks. Disturbing or destroying these marks reduces geodetic control available to local surveyors. Please make every effort to preserve this valuable network.
Mark Resets
If a mark is about to be destroyed (e.g., due to planned construction), it may be possible to reset the mark and retain the geodetic control. Review the Bench Mark Reset Procedures or contact your closest geodetic advisor. Please do not attempt to reset a mark that has been separated from the base. Any remnants of destroyed marks must be properly discarded and not reused in any manner, as this is a violation of Federal law.
Destroyed Marks
If it is determined that a mark has been destroyed, please provide enough photo evidence to show how this determination was made. To submit this information to NGS, follow the instructions regarding “destroyed marks” on the Survey Mark Recovery page.
Contact Us
NGS will review abandonment notices and answer questions.
Regional Geodetic Advisors can consult on local issues.
Surface Transportation Board can file additional comments from concerned surveyors.
