49 C.F.R. § 671.35 – Lone worker.

(a) On-track safety and supervision. The RTA may authorize lone workers to perform limited duties that require fouling a track.
1. (1) The lone worker must be qualified as a roadway worker in charge and lone worker under the RTA's training and qualification program as specified in § 671.41.
2. (2) The lone worker may perform routine inspection or minor tasks and move from one location to another. The lone worker may not use power tools and may only access locations have defined in the track access guide as appropriate for lone workers, i.e., no loud noises, no restricted clearances, etc.
3. (3) The lone worker may not use individual rail transit vehicle detection, where the lone worker is solely responsible for seeing approaching trains and clearing the track before the trains arrive, as the only form of on-track safety.
(b) Communication. Each lone worker must communicate prior to fouling the track with a supervisor or another designated employee to receive an on-track safety job briefing consisting of the elements in § 671.33(b), including a discussion of their planned work activities and the procedures that they intend to use to establish on-track safety. The lone worker must acknowledge and document the job safety briefing in writing consistent with § 671.33(c).