49 U.S.C. § 20107 — Inspection and investigation

(a) General. To carry out this part, the Secretary of Transportation can take actions considered necessary, including: (1) conducting investigations, making reports, issuing subpoenas, requiring documents, taking depositions, and setting recordkeeping and reporting requirements; and (2) letting a public entity or qualified person handle inspecting, examining, and testing railroad equipment, facilities, rolling stock, operations, and people.

(b) Entry and Inspection. To carry out this part, an officer, employee, or agent of the Secretary can, at reasonable times and in reasonable ways, enter and inspect railroad equipment, facilities, rolling stock, operations, and relevant records. If asked, they must show proper credentials. During an inspection, that person counts as a United States government employee under chapter 171 of title 28.

(c) Railroad Radio Communications.
(1) In general. To carry out the Secretary's duties under this part and chapter 51, the Secretary can authorize officers, employees, or agents to do the following, openly or secretly, when the Secretary finds it reasonable: (A) intercept a radio communication, with or without the consent of the sender or other receivers, but only if the communication is broadcast or transmitted over a radio frequency that (i) the FCC authorized for use by one or more railroad carriers, and (ii) railroad carriers mainly use for communications about railroad operations; (B) communicate the existence, content, substance, purport, effect, or meaning of the communication, subject to paragraph (3); (C) receive or help receive the communication or any information in it; (D) disclose the content, substance, purport, effect, or meaning of the communication, or use the communication or information in it, subject to paragraph (3), after receiving it or learning its contents; and (E) record the communication by any means, including writing or tape recording.
(2) Accident and incident prevention and investigation. The Secretary, and authorized Department of Transportation officers, employees, and agents, can engage in these activities to prevent and investigate accidents and incidents.
(3) Use of information. (A) Information gathered this way can't be admitted as evidence in an administrative or judicial proceeding, except (i) to prosecute a felony under federal or state criminal law, or (ii) to impeach evidence offered by a party other than the Federal Government about the existence, electronic characteristics, content, substance, purport, effect, meaning, or timing of, or the identity of parties to, a communication intercepted under paragraphs (1) and (2), in proceedings under sections 5122, 5123, 20702(b), 20111, 20112, 20113, or 20114 of this title. (B) If such information is admitted for impeachment under (A), the court, administrative law judge, or other officer conducting the proceeding can issue protective orders about its confidentiality or use, as appropriate to protect privacy and administer justice. (C) Evidence can't be excluded from a proceeding just because the government wouldn't otherwise have learned of it or obtained it if not for intercepting information that is not admissible under (A). (D) This information isn't subject to publication or disclosure, or to search or review connected with publication or disclosure, under section 552 of title 5. (E) Nothing in this subsection limits or otherwise affects the United States' authority under another law to intercept a communication, and to collect, retain, analyze, use, and disseminate the information obtained through that interception.
(4) Application with other law. Section 705 of the Communications Act of 1934 (47 U.S.C. 605) and chapter 119 of title 18 don't apply to conduct authorized by and under this subsection.