(a) With respect to any company or person owned or controlled by one or more carriers or under common control therewith, performing a service or operating equipment in connection with the transportation of passengers or property by railroad, or the receipt, delivery, elevation, transfer in transit, refrigeration or icing, storage, or handling of property transported by railroad, but which is principally engaged in some other business, the Board will require the submission of information pertaining to the history and all operations of such company or person with a view to determining whether it is an employer or whether some identifiable and separable enterprise conducted by the person or company is to be considered to be the employer, and will make a determination in the light of considerations such as the following:

(1) The primary purpose of the company or person on and since the date it was established;

(2) The functional dominance or subservience of its business which constitutes a service or operation of equipment or facilities in connection with the transportation of passengers or property by railroad in relation to its other business;

(3) The amount of its business which constitutes a service or operation of equipment or facilities in connection with the transportation of passengers or property by railroad and the ratio of such business to its entire business;

(4) Whether such service or operation is a separate and distinct enterprise;

(5) Whether such service or operation is more than casual, as that term is defined in § 202.6.

(b) In the event that the employer is found to be an aggregate of persons or legal entities or less than the whole of a legal entity or a person operating in only one of several capacities, then the unit or units competent to assume legal obligations shall be responsible for the discharge of the duties of the employer.