Model Railroader – September 2019

BY EXPERI-

MENTING WITH

DIFFERENT

SIZES OF

TUBING, I’VE

MADE HEAD-

LIGHTS AND

CLASS LIGHTS

USING FIBER-

OPTIC TUBING.

• LARRY

September 2019 61

and in some cases even drop-
ping resistors, already
attached. These can either be
glued to the backside of a
clear plastic insert for a head-
light, as I’ve shown in the
past, or glued directly to a
surface if other types of lights
are to be modeled. Keep in
mind that light bulbs typi-
cally are rated at anywhere
from 1.5 to 16 VDC and
25-80 mA current, whereas
white LEDs only require
about 3VDC at 20 mA.

If a clear plastic casting or
insert isn’t available for a
light, then it’s possible to
make one out of plastic light
tubes. These rods of varying
diameter are often referred to
as fiber-optic tubing. By hold-
ing the end of the tubing over
a heat source such as a small
candle, it will melt and form a
rounded surface.
By experimenting with
different sizes of tubing, I’ve
made headlights and class
lights using fiber-optic tub-
ing. If you need to illuminate
several lights at the same
time, such as class lights, step
lights, or truck lights, fiber-
optic tubing can be used and
glued in position. Then the
free ends can be gathered and
covered with heat-shrink tub-
ing and fitted over a grain of
rice bulb or an LED ❷.
It’s an easy matter to drill
out the dimple or
pimple on a plastic
shell and insert a
bulb with the tip
serving as a lens
for a class light.
I typically use a
drop of clear
acrylic cement,
such as Testor’s
Clear Parts
Cement or canopy
glue, to stabilize it.
You can also drill
a hole in the back
of a clear plastic
lens and glue the
bulb into it. Con-
nect the wires to a

function lead and you’re

ready to go. You may be able

to install fiber-optic tubing in

the same way after forming

the end into a lens.

Rotary beacons and flash-

ers are relatively easy to

model, since many companies

make castings for these, some

with cored lenses to accept

lights. I’ve also

drilled a small

hole in the dome

castings and

inserted a small

light bulb or LED

from the bottom

❸. You could also

try using a piece

of fiber-optic tub-

ing to light the

fixture. Most

decoders provide

for rotary and

flashing beacons,

and a single func-

tion would power

the required bulb

or LED.

Mars and Gyralites can be

modeled by gluing an SMD

LED to the rear of the plastic

lens or drilling a small hole

for a light bulb or fiber-optic

tubing. Most decoders also

have programming capability

to make a headlight flash like

one of these.

To light number boards

separately from the headlight,

you may have to cut the lens

and number board casting

apart using a razor saw. Then,

I would paint the casting

exterior black, except for the

face, and drill a small hole in

which to insert a small bulb

to light it. Alternatively you

could drill a small hole and

insert fiber-optic tubing in all

the number boards and use a

single bulb or LED to light

them simultaneously. Most

number board decals will

glow if they’re applied to the

number board lenses.

Ditch lights are common

on many new models, and

aftermarket detail kits for

them that typically include

either a microbulb or LED are

readily available. Just install

them and connect the wires

to the desired decoder func-

tion output.

Truck and step lights are

pretty easy using SMD LEDs

or fiber-optic tubing. I glued

the LED and its wires to the

underside of the chassis using

cyanoacrylate adhesive (CA)

❹ and wired them all to a

single function.

Lights can add life to your

locomotives and a touch of

drama to your model rail-

road. While it may be overkill

to outfit a whole fleet with

special lighting effects, having

a few strategically placed

models is definitely worth the

extra effort. For more infor-

mation on the various materi-

als and methods used in this

article, visit my website

(www.dccguy.com).

By Larry Puckett

Beacon casting drilled for bulb

Bulb inside dome

Surface-mount LED

❷ Fiber optics. When using multiple pieces of fiber optic tubing, the free ends can be

gathered and inserted into a piece of heat-shrink tubing, which is then fitted over a grain-of-

rice bulb, or an LED as shown here.

❸ Special effects. Beacon or strobe castings

can be drilled out and a bulb, as Larry did on

this model, or LED inserted. Details West offers

several rotary beacons with lenses that are

already cored to accept illumination.

❹ Truck lights. Truck and step lights can be

modeled by gluing SMD LEDs to the chassis

and then running the wires to the decoder.

The LED is glued to a piece of Kapton tape

on the metal frame to prevent a short.