I've never heard of a rule that says PV's need an extra conductor. Where did you hear that?
Here's the rule from
Amtrak
5. When occupied private cars are traveling on Amtrak, the following criterion applies:
a) A person-in-charge will be identified for all private car moves. The person-in-charge of the private car
must be identified on the private car movement request form when it is submitted to Amtrak s System
Operations Department and their name indicated on the Passenger Name Record (PNR).
b) The person-in-charge of the private car must meet with the Conductor at the originating point of their trip
and they must discuss the emergency plan for the private car. In addition, they must discuss the
evacuation plan along with a method of communication in the event of an emergency.
c) The person-in-charge of the private car must also complete a new Form NRPC 3160 Private Car
Passenger Record (see attachment 2) that identifies all passengers that will be on-board the private car.
The person-in-charge will give the completed form(s) to the Conductor, who will place these
document(s) in the Train Collections Pouch. If the NRPC 3160 form is unavailable, form NRPC 3085
On-Board Passenger Record may be substituted.
d) The person-in-charge of the private car must not be under the influence of alcohol or drugs throughout
the trip.
e) In the event that a Private Car Owner cannot meet these requirements, Amtrak will provide an additional
crew member to accompany the car at the Owners expense.