Actually, running with the dummy A unit in front is not a bad idea. Often with older engines, kids only ran with the powered unit first, and seldom went in reverse. So the gears ended up wearing in one direction. Running powered unit last in the consist and in reverse evens out the wear. Plus it is less strain on the coupler, as you are pushing 1-3 units that otherwise would be pulled. As long as the motors and layout can handle it, you can run a longer train.
Chris
LVHR