20 C.F.R. § 255.2
Overpayments
An overpayment, within the meaning of this part, is made in any case in which an individual receives a payment under the Railroad Retirement Act, all or part of which payment he or she is not entitled to receive.
An overpayment, within the meaning of this part, is made in any case in which an individual receives a payment under the Railroad Retirement Act, all or part of which payment he or she is not entitled to receive.