This is rough, and could vary somewhat, but may help see how two iso rails or twenty doesn't matter. (each square is a power supply, could be constant, could be varible.)
It also shows the lamp with a common to the rail when it could go to the traƱsformer common too.
The #1 #2 #3 leads can't even be seen in the service diagram, but the light either needs it's own wiring because of using the iso rail triggers OR needs the relay for the tower action to be switched on/off on the hot leg.