I have built a turnout (switch) control and protection board for use with my MTH RealTrax remote controlled turnouts. The MTH switch solenoids require 10 volts at 1.25 amperes to activate remotely.
I operate these turnouts via the MTH AIU. An individual 18 V AUX power circuit is used. Track voltage is NOT used. To protect against a short circuit I have installed limiting resistors and individual fuses for these control circuits.
In the event of a single failure (short) the current to each solenoid is limited to no more that 1.75 amperes per solenoid or 4 amperes maximum due to fuse protection. Any fault will not affect any other circuit. The turnout control and protection board (shown) is used with an 8 channel fuse box (not shown). An individual 18 V AUX power circuit is used.
