28 4-6-4 J3a Hudson Steam Locomotive
TIU
POWER
SOURCE
(-)
to outside rail
(-)
to transformer ground
or black
(+)
to inside rail
(+)
to transformer power
or red
Orient Locomotive
So That Right Side
Wheels Are On The
Ground (-)
Track Rails
Unlike AC layouts that utilize 3-rails, DC layouts treat each rail as the positive or
negative conduit from the transformer. Because DCS deploys its digital signal
through the positive terminal, it is possible on 2-rail DC layouts to transpose the signal
to the wrong track rail. 2-Rail locomotives equipped with Proto-Sound 2.0 will be
unable to receive the DCS signal if the right side wheels (think of the right side of the
locomotive from the perspective of sitting in the cab) are not on the Ground or - rail.
Should that occur, the locomotive will not respond to DCS commands. Reversing the
orientation of the locomotive or the wiring will resolve the transposed signal. The
DCS Polarity Switch can also be used to reverse the electrical orientation of the engine
to the rails. (See Page 7)
