(c) The term “employee representative” means any officer or official representative of a railway labor organization other than a labor organization included in the term “employer” as defined in subsection (a) who before or after August 29, 1935 , was in the service of an employer as defined in subsection (a) and who is duly authorized and designated to represent employees in accordance with the Railway Labor Act, as amended [ 45 U.S.C. 151 et seq.], and any individual who is regularly assigned to or regularly employed by such officer or official representative in connection with the duties of his office.
45 USC § 231(c)
For the purposes of this subchapter