20 CFR § 226.61 - Use of military service.
(a) Claim for use of military service. An employee is deemed to have filed a claim for the use of military service and earnings as service and compensation under the Railroad Retirement Act if -
(1) The employee indicates on the annuity application or another signed statement that he or she has military service;
(2) The employee does not specifically request that the military service be credited as wages under the Social Security Act;
(3) The military service is creditable under the Railroad Retirement Act, as shown in part 212 of this chapter; and
(4) Using the military service as railroad service and compensation would be to the employee's advantage (the employee and his or her family would receive higher total benefits than if the military service were credited under the Social Security Act).
(b) Effective date for use of military service. Military service can be used as service and compensation under the Railroad Retirement Act starting with the date the annuity begins but no earlier than twelve months before the employee files an application or statement showing that he or she has military service.