There are authorized to be appropriated to the railroad unemployment insurance account, without fiscal year limitation, such amounts as may be necessary to carry out the provisions of this chapter. The amounts so appropriated shall be transferred from time to time to the railroad unemployment insurance account on the basis of estimates by the Secretary of the Treasury after consultation with the Railroad Retirement Board of the amounts required from time to time to carry out the provisions of this chapter. Amounts so transferred shall be repayable advances without interest.