Oh, I get it. You want to fool the transformer into thinking it is powering a smaller layout by removing part of the load (track) with your switches.
I don't think this is going to achieve what you think it will. When track is powered and no engine is running on it there is virtually no load, so you won't be conserving much by turning off the other block(s). The current draw is going to try to take a straight line path to the engine as it moves around the track. The engine is a complex load that changes as it moves along the track. Wire is sized based on the expected amperage and length of the run. Turning off a block does not change how much current is flowing to the engine.
