Stan and others, only the older 4002 3-way adaptor (1 amp) comes apart like your photo shows. The newer 4006 (2 amp) version has the 3 plugs permanently connected to the main feeder wire - and that feeder wire comes apart from the transformer.
fwiw, I swapped out the 4006 transformer for the 1-amp version and sure enough the voltage came down to around 5 volts, lights are what I call normal brightness. That's for 5 buildings.