Using wire that can safely carry the maximum current that your transformer can put out, connect the transformer common to the outside rails generally. Connect the center rail of each track block to the center terminal of one SPDT switch. Connect each of the outer terminals of each SPDT switch to one of the variable-voltage terminals of the transformer.
When the switch corresponding to a block is in one position, the block will be controled by one transformer control. When that switch is in the other position, the block will be controlled by the other control. If you use center-off switches (SPDT-CO), the block will be unpowered when the switch is in the center position.
If you post the transformer model, we may be able to tell you which terminal is common and which are variable, as well as what gauge wire to use. Note that a transformer puts out alternating current, so there is no positive nor negative.
Bob Nelson
The power bus line does not go back to the transformer, just as the common does not go back. As Bob posted, connect the center terminal of the SPDT switch to the power wire, and one of the other tabs to the center rail connection of a lockon. If you connect as you posted, you will short out the transformer when you throw the switch to any position.
Larry
"Connect the center rail of each track block to the center terminal of one SPDT switch."
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