Track switches can be a cause of train derailments when the engineer inadvertently operates a switch control lever when a train is over the track switch. The 2RC controller can be used to inhibit operator switching action.

Three-Rail Innovations' Two Relay Controller is connected to remove power to the track switch mechanism whenever a train is near or spanning the switch.

The following drawing shows the 2RC configured to inhibit an operator switch control (an electrical switch) whenever a train enters any of the isolated outside-rail blocks leading to the track switch. The track switch operation is restored when the train leaves the isolated outside-rail blocks.

The example powers the 2RC with a 12-14 volt transformer and the outside-rail inputs with an 8-20 volt transformer.

The example shows a conventional solenoid-operated track switch that uses a source of "track common," usually supplied via the center post of the switch, to activate the switch motor. To inhibit operator switching activity, the common wire of the switch controller is connected to "track common" through the C (Common) and NC (Normally Closed) relay terminals. When the relay is OFF, the switch control is operative. When the relay is ON, the switch control will not change the setting of the track switch, and the indicator lights will go off. Track switching for non-derailing functions will still operate as usual.

Multiple, adjacent track switches can be inhibited with the same relay. Install isolated outside-rail track blocks at the beginning of each route through the switches and connect them to the 2RC input. Connect all the operator switch controls' common wires together and to the relay terminal.

Each of the S, C, and T isolated outside-rail track blocks is connected to the 2RC outside-rail input. Combining diodes are shown so the three isolated outside-rail track blocks can be used to operate other features, perhaps switch non-derailing; otherwise, direct connections can be made.

The 2RC jumpers are configured for the NO V feature set and the OFF/ON feature for Relay-1. Relay-2 is available for another feature.

Relay-1 is ON whenever a train is in any of the connected isolated outside-rail track blocks.

Other Two Relay Controller features can be used to inhibit operator switch controls. The "Train-Between-Track-Blocks" feature set and the can be used to inhibit operator switching action when a train is within or between track blocks.

Too many train derailments over track switches? You need Three-Rail Innovations' Two Relay Controller.

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