Model Forum / General / Railroads / April 2004

A DC powersupply and a DCC power supply applied to the same section of
track at the same time will probably NOT produce good results.

I run my Digitrax equipped loco's on a DC only layout with no problems.
I selected "yes" to that option when programming the decoder on an NCE
system.

Paul

The DCC analogue control works reasonably well with large motors - what is
happening is that the alternating pulses of one polarity are extended,
imagine 14 volts for a 10 thousandth of a second  in one direction and
then 2/10 thousandths in the opposite direction. A motor armature with
plenty of mass (Athearn for example) will just revolve in the one
direction and the extra heat will just disipate.
On a little motor such as a Roco model with an N gauge motor, the motor
will keep reversing with the voltage and while the outward effect will be
forward motion the mechanisim will take a pounding.
The high voltage will also cause severe heating and occassionally
melt-down.

All DCC decoders should work with it, but only to the standard of the Roco
unit, such as limited numbers of addresses, limited speed steps and
limited numbers of functions.
If those limitations suit your purposes then that is the unit for you,
otherwise you will have to dig deeper into your beer money!

Regards,
Greg.P.

I can't comment on #2 but I'll elaborate on your first question.
BTW, it is Roco, not Rocco.

DCC was never designed to be able to co-exist with DC.  You cannot have both
hooked up to the same track.  Things would fry !

However, most DCC systems have an "analog" mode avaialble where they can
give you control to a plain DC locomotive on the same track as the DCC
controlled locos.  They can all be simultaniously controlled.

This is done by creatively changing timing to the DCC signal present in the
tracks.  It gives an averaged out pulse DC voltage which can control a plain
CD motor.  Since the signal is still DCC, it makes the motor hum and get warm
even when it is sitting still.  It also doesn't play well with coreless motors.
The DCC equipped locos don't still work as they suppose to. Unless their
headlight use simplified wiring whuch would cause headlights to dim when using
the CD loco on the DCC district.  No biggie.

Overall, it is not really recommended to run DC and DCC locos on the same
track.

On the other hand, most DCC decoders work well when placed in CD environment.
Some are DC enabled by default, others have to be enabled to do so.
They just need a higher starting voltage (as the decoder needs some voltage to
function properly).

Peteski