49 CFR §240.104

1. (a)A railroad is not required to use a certified locomotive engineer to perform the following functions:
   1. (1)Operate specialized roadway maintenance equipment; or
   2. (2)Operate a dual purpose vehicle that is:
      1. (i)Being operated in conjunction with roadway maintenance and related maintenance of way functions, including traveling to and from the work site;
      2. (ii)Moving under authority of railroad operating rules designated for the movement of roadway maintenance equipment that ensure the protection of such equipment from train movements; and
      3. (iii)Being operated by an individual trained and qualified in accordance with §§ 214.341, 214.343, and 214.355 of this chapter.
2. (b)A railroad is required to use a certified locomotive engineer when operating a dual purpose vehicle other than in accordance with paragraph (a)(2) of this section.