CFR›Title 49›Subtitle B›Chapter VIII›Part 831›Subpart D ContainsSection 831.40CorpusDaily eCFRDisplayed edition2026-04-27Last updated2026-04-27 Subpart D—Railroad, Pipeline, and Hazardous Materials Investigations Sections 831.40 § 831.40 Authority of NTSB in railroad, pipeline, and hazardous materials investigations. Previous C Subpart C—Highway Investigations Next E Subpart E—Marine Investigations