If I delay my Railroad retirement until age 70 does my spouses tier 1 benefit stop growing at my full retirement age (67) or does it keep growing until I retire at 70 ?

Hi. I'm sorry but my expertise is limited to Social Security benefits so I can't give you a definite answer. Unreduced Social Security spousal benefits are based on 50% of the worker's primary insurance amount (PIA), which is equal to the worker's full retirement age (FRA) rate. Social Security spousal benefits do not increase if the worker waits until age 70 to claim their benefits.

I know that Tier 1 RR benefits are patterned after Social Security, but although I assume that the same holds true for Tier 1 spousal benefits I'm not positive. I would suggest directing your question to the Railroad Retirement Board for a definite answer.

Best, Jerry