20 CFR §216.43

1. (a)Employee annuity. A supplemental annuity that begins after December 31, 1974, does not affect the payment of a regular employee annuity. A supplemental annuity beginning prior to 1975 causes a reduction in the employee annuity as provided by section 3(j) of the Railroad Retirement Act of 1937.
2. (b)Spouse or survivor annuity. The payment of a supplemental annuity does not affect the amount of a spouse or survivor annuity.
3. (c)Residual lump-sum. The amount of a supplemental annuity is not deducted from the gross residual lump-sum benefit. See part 234 of this chapter for an explanation of the residual lump-sum benefit.