26 CFR 31.3231(c)-1: (c)-1 Who are employee representatives.

(a) An employee representative within the meaning of the act is—

(1) Any officer or official representative of a railway labor organization which is not included as an employer under section 3231(a) who—

(i) Was in the service of an employer either before or after June 29, 1937, and

(ii) Is duly authorized and designated to represent employees in accordance with the Railway Labor Act.

For railway labor organizations which are employers under section 3231(a), see paragraph (a) (5) and (6) of § 31.3231(a)-1.

(2) Any individual who is regularly assigned to or regularly employed by an employee representative, as defined in paragraph (a)(1) of this section, in connection with the duties of such employee representative's office.

(b) In determining whether an individual is an employee representative, his citizenship or residence is material only insofar as those factors may affect the determination of whether he was “in the service of an employer” (see paragraph (a) of § 31.3231(b)-1).