[Code of Federal Regulations] [Title 20, Volume 1] [Revised as of April 1, 2005] From the U.S. Government Printing Office via GPO Access [CITE: 20CFR225.21] [Page 429] TITLE 20--EMPLOYEES' BENEFITS CHAPTER II--RAILROAD RETIREMENT BOARD PART 225_PRIMARY INSURANCE AMOUNT DETERMINATIONS--Table of Contents Subpart C_PIA's Used in Computing Survivor Annuities and the Amount of the Residual Lump-Sum Payable Sec. 225.21 Survivor Tier I PIA. The Survivor Tier I PIA is used in computing the tier I component of a survivor annuity. This PIA is determined in accordance with section 215 of the Social Security Act using the deceased employee's combined railroad and social security earnings after 1950 (or after 1936 if a higher PIA would result) through the date of the employee's death.