the DCC bus and to the frog. It matches the polarity of the frog
to whatever is needed when the loco crosses over it.
A wye [2] requires that one of the three legs be double gapped
on the exit side of its turnout. In this example, the straight and
diverging routes of the turnout on the right side of the wye are
double gapped.
While model turntables can physically reverse a locomotive,
and, perhaps, a single car, they may or may not reverse polarity
as they turn. Some will designate a “dead zone” to be oriented
where there are not tracks coming into the turntable. This is
usually a giveaway that the turntable reverses polarity.
If the turntable does not reverse track polarity as it turns
around, an auto-reverser will be needed. More information
is on my web site at the bottom of the page on layout wiring
.
5. Testing a layout with a marked truck.
DCC IMPULSES |
8
