Hope people dont think I'm dragging this transformer powering blocks issue too much but I did further research. There are a series of soft cover books by Peter Riddle "Wiring Your Lionel Layout" Volume 1 through 3. I'm looking at Volume 2, copy right 1993, Chapter 5, page 31 where there is a very clear diagram of two blocks connected to one transformer where one block is powered by a terminal A and the other block by terminal B. That is just one specific example from these series of books where this technique is used. Going back to Dales example of connecting the A and D terminal, that is not the true picture of what happens when the front roller say is on the A terminal and rear roller is on the D terminal. There is a load in the circuit, the motor, and there is a third connection, the common ground.
Another publication using this technique is The Lionel Train Book, copy right 1986, chapter 9 page 62 where they have two blocks and a chart showing the connections to various Lionel transformers including the PWZW. In the example one block is connected to either A or D and the other block is connected to B or C. How can all these books be wrong?