Relays.

Each relay, the functioning of which affects the safety of train operations, shall be tested at least once every four years except: (a) Alternating current centrifugal type relay shall be tested at least once every 12 months; (b) Alternating current vane type relay and direct current polar type relay shall be tested at least once every 2 years; and (c) Relay with soft iron magnetic structure shall be tested at least once every 2 years. [49 FR 3384, Jan. 26, 1984]