60 http://www.ModelRailroader.comPrototype diesel locomo-
tives have a lot more lights
than just headlights. A diesel
locomotive might have a
rotary beacon or flasher on
the roof, a Mars or Gyralite
along with the headlight and
rear light, number board
lights, classification lights
on the four corners (cab
units would have only two),
step lights, truck lights, ditch
lights, cab interior lights, and
possibly marker lights.
The main problem you’ll
face in modeling all these
lights will be finding a
decoder with enough func-
tions to power them. Since
most decoders max out at six
functions, you’ll need to make
compromises. Because class
lights would only be used on
extras and sections, they seem
expendable. I’d also eliminate
the cab light and engine room
light. Combining the number
boards and headlights, as is
common on many models, is
another reasonable compro-
mise. You could also combine
the truck and step lights on a
single function. So you can
easily get down to a manage-
able number of functions.For this project, I wanted to
install a sound decoder withstay-alive and speaker as well
as a number of lights. To
meet these needs, I chose a
TCS WOWSound 21MTC
version 4 “prime” decoder ❶
with recently added diesel
engine sounds (four Baldwins,
Alco 539T, General Electric
“ES44CW” GEVO).
Most importantly, it has
six functions in addition to
the front and rear headlight.
Since the functions can sup-
port up to 100 mA each, you
should be able to operate fourto five light-emitting diodes
(LEDs) or appropriately rated
bulbs on each.
As I explained in the June
DCC Corner, the 21MTC
decoders are essentially plug-
and-play once a proper moth-
erboard is installed. For that
I used a Decoder Buddy from
NixTrainz (www.nixtrainz.
com) ❶. This board is inter-
esting in having a plug-in
adapter with solder tabs for
six function wires in additionto tabs on the board for the
track pickups, speaker, and a
stay-alive.
I test fit both TCS KA1
and KA2 Keep-Alives and
found the KA1 worked best
in this space. TCS has rede-
signed its Keep-Alives using
smaller components, making
them about half the size of
their predecessors. The
speaker is a 10mm x 15mm
sugar cube from Streamlined
Backshop (www.sbs4dcc.
com) attached to the shell and
connected to the Decoder
Buddy with a TCS 2-pin
mini-connector.For lights you have a couple
options. Circuiton and
Miniatronics in particular
offer incandescent bulbs in a
range of sizes and colors suit-
able for locomotive lights.
Another option is small sur-
face mount device (SMD)
LEDs. These come in a range
of sizes, and at the small end
it can be very difficult to even
see them, much less solder on
a pair of wires.
Fortunately companies
like Ngineering, Richmond
Controls, Streamlined
Backshop, and others offer
miniature LEDs with wires,DCC Corner
Light up the night with DCC
The addition of lights can create a dramatic scene on a model railroad. However, this
inspirational scene is photographed on the prototype in 1969 by Ron Flanary at Andover, Va.,
on the old Interstate RR. Ron Flanary photo❶ Fully functional. The Decoder Buddy from NixTrainz is an excellent motherboard for
installing a 21MTC decoder like this WOWSound 4 Prime diesel sound decoder. The board also
has solder tabs for track pickups, speakers, stay-alive, front and rear headlights, and up to six
additional functions. A TCS 2-pin mini-connector was used to power the speaker.TCS 2-pin mini connector
Plug for lights, etc.Keep-Alive21MTC TCS decoderDecoder Buddy