49 CFR § 220.11 - Requirements for roadway workers.
(a) On and after July 1, 1999, the following requirements apply to a railroad that has 400,000 or more annual employee work hours:
(1) Maintenance-of-way equipment operating without locomotive assistance between work locations shall have a working radio on at least one such unit in each multiple piece of maintenance-of-way equipment traveling together under the same movement authority. The operators of each additional piece of maintenance-of-way equipment shall have communications capability with each other.
(2) Each maintenance-of-way work group shall have intra-group communications capability upon arriving at a work site.
(b) On and after July 1, 1999, each employee designated by the employer to provide on-track safety for a roadway work group or groups, and each lone worker, shall be provided, and where practicable, shall maintain immediate access to a working radio. When immediate access to a working radio is not available, the employee responsible for on-track safety or lone worker shall be equipped with a radio capable of monitoring transmissions from train movements in the vicinity. A railroad with fewer than 400,000 annual employee work hours may provide immediate access to working wireless communications as an alternative to a working radio.
(c) This section does not apply to:
(2) Railroad operations where the work location of the roadway work group or lone worker:
(i) Is physically inaccessible to trains; or