May 2011 article

[AlanPostWar]

May 2011 CTT article title Two Trains One Mainline Zero Collisions 

Paragraph titled Wiring the circuit "After installing the track and positioning the 153IR device, I wired the layout for automatic operation. I used black 18gauge stranded wire to connect all the outside rails to the ground post, normally labeled U". 

OK that makes sense. 

"Except within the established blocks, I used red 18 gauge stranded wire to connect all but but the center rails within the previously established blocks to the variable post normally labeled A..."

Does not make sense. 

Unless I am reading this incorrectly why would outside rails that are normally ground be wired to the hot post on the transformer.