55031 Relay Decoder (All Scales) $44.99 Default Title - $44.99 Quantity Please fill in the form below if you'd like to be notified when it becomes available. 55031 Relay Decoder (HO/N/TT-Scales) The PIKO Switch Decoder allows up to 2 solenoid devices (like switches or signals) to be switched. Instructions for the 55030/55031 Decoders