49 CFR §242.107

1. (a)Each railroad's program shall state which of the two types of service (conductor and passenger conductor), provided for in paragraph (b) of this section, that it will cover.
2. (b)A railroad may issue certificates for either of the following types of service:
   1. (1)Conductor; and
   2. (2)Passenger conductor.
3. (c)A railroad shall not reclassify the certification of any type of certified conductor to a different type of conductor certification during the period in which the certification is otherwise valid except when a conductor completes the emergency training identified in part 239 of this chapter and is certified as a passenger conductor.
4. (d)Each railroad is authorized to impose additional conditions or operational restrictions on the service a conductor may perform beyond those identified in this section provided those conditions or restrictions are not inconsistent with this part.