unemployment insurance wages
(B)If more than one-half of remuneration paid by an employer to an employee during any year is remuneration for service described in section 3306(c)(9), the term “unemployment insurance wages” means, with respect to such employee for such year, an amount equal to so much of the remuneration paid to such employee during such year which would be subject to contributions under section 8(a) of the Railroad Unemployment Insurance Act () if the maximum amount subject to such contributions were $500 per month.