@ADCX Rob posted:Don't the wheelsets make the connection to the other rail through the axles? A 12 car train would have at least 48 connections to the other rail.
Not always, what happens if you have a break in a block. ( ie wire comes loose. ) if you have both rails powered you don't have to worry about that, do you?
Switches and crossover can cause problems also
Bottom line what does it hurt to be safe. How much harder is it to do one lead outside rail and the next on the inside rail.