§ 42. Contractual relationship.

Upon becoming either a Class A, a Class B or a Class C member of the Employees' Retirement System, or upon becoming a member of the Fire and Police Employees' Retirement System, established under this Article 22, such member shall thereupon be deemed to have entered into a contract with the Mayor and City Council of Baltimore, the terms of which shall be the provisions of this Article 22, as they exist at the effective date of this ordinance, or at the time of becoming a member, whichever is later, and the benefits provided thereunder shall not thereafter be in any way diminished or impaired.