20 CFR § 218.9 - When an employee annuity begins.
(a) Full-age annuity—employee has completed 10 years but less than 30 years of service. An employee full-age annuity begins on the later of either the date chosen by the applicant or the earliest date permitted by law. The earliest date permitted by law is the latest of—
(1) The day after the day the claimant last worked for a railroad employer;
(2) The first day of the month in which the claimant attains full retirement age; or
(3) The first day of the sixth month before the month in which the application is filed.
(b) Reduced-age annuity—employee has completed 10 years but less than 30 years of service. An employee reduced-age annuity begins on the later of either the date chosen by the applicant, or the earliest date permitted by law. The earliest date permitted by law is the latest of—
(1) The day after the day the claimant last worked for a railroad employer;
(2) The first day of the first full month in which the claimant is age 62; or
(3) The first day of the month in which the application is filed if the claimant does not have a spouse (or divorced spouse) who would be entitled to a retroactive unreduced spouse (or divorced spouse) annuity. If the claimant has such a spouse (or divorced spouse) the claimant's annuity can begin on the first day of the month in which the spouse (or divorced spouse) annuity begins.
(c) Disability annuity. An employee disability annuity begins on the later of either the date chosen by the applicant or the earliest date permitted by law. The earliest date permitted by law is the latest of—
(1) The day after the day the claimant last worked for a railroad employer;
(2) The first day of the twelfth month before the month in which the application is filed;
(3) The first day of the sixth month after the month of disability onset; or
(4) The first day of the month of disability onset if the claimant was previously entitled to an employee disability annuity which ended within five years of the current disability onset month.
(d) Annuity based on at least 30 years of service. An employee annuity based on at least 30 years of service begins on the later of either the date chosen by the applicant or the earliest date permitted by law. The earliest date permitted by law is the latest of—
(1) The day after the day the claimant last worked for a railroad employer;
(2) The first day of the first full month in which the claimant is age 60 and will accept a reduced annuity;
(3) The first day of the month in which the claimant attains age 62; or
(4) The first day of the sixth month before the month in which the application is filed.