CPR Galt Subdivision
A Sound Improvement
By Steve Bourdon, CVR Staff Consultant
Enhance the Sound in a Rapido Trains FPA-4
modellers would agree that a sound-equipped locomotive is much more pleasing to
operate than the alternative. That is probably why most of us reserve or
purchase locomotives having factory installed DCC with sound.
However, although manufacturers may strive to produce high quality models,
factory-equipped DCC and sound doesn’t always mean you are getting the best
case in point is the recently released Rapido Trains FPA-4 with factory-equipped
ESU DCC and sound. I must admit
that I was favourably impressed with the sound and performance of this model
when I first operated it on my model railway. However,
after I attended an ESU Loksound workshop in Scranton, PA., I learned about how
to make a simple improvement in the sound produced by this model.
that conference, one of the attendees, Roger Eicher, asked if I had purchased
any of the Rapido Trains FPA-4 locomotives with DCC/sound, to which I confessed
that I had. After I told him how
happy I was with my model, he indicated that he improved the sound simply by
changing out the OEM speaker and installing an ESU Loksound 28mm speaker (PN
50333). Since the decoder in the Rapido FPA-4 is an ESU product, the 4-ohm ESU
Loksound speaker is compatible.
After Roger completed his installation, he turned on the sound and blew the
windows out of his basement! (His words.) Of course he was exaggerating, but
after he explained how easy it was to do the modification and the impressive
results, I thought I’d give it a try.
Compare the original speaker with the ESU Loksound 28mm speaker assembly (PN
first step is to remove the shell.
The instructions in the manual state that all you need to do is to remove the
couplers, and then wiggle the shell off the chassis. It’s that easy, so says
Well, folks, it ain’t that easy. They forgot to mention one little detail. The
side railings that are located halfway down both sides of the body are attached
to the chassis at the bottom. Removing them is easy, simply by gently pulling
them out using tweezers. After you have removed the bottom part of the four
railings from the holes in the chassis, as well as the couplers,
then you can easily remove the shell.
next step is to remove the original speaker, which is installed on top of the
chassis next to the decoder assembly. The speaker is held in place by a bracket
that is screwed into the chassis. Remove
the two screws and lift out the assembly. Next, remove the speaker from the
assembly, slide the two insulation tubes back and cut the wires from the speaker
terminals. Set aside the speaker
assembly for future use in another project.
prepare the ESU 28mm replacement speaker for installation, first remove it from
the baffle. Then solder short wires to the terminals on the speaker.
I used brown 36ga ESU Loksound wire (PN51948). Before placing the speaker
back into the sound baffle, cut off the lugs from the side of the baffle and
sand the exterior surface until smooth.
Install the speaker in the baffle, with the two speaker wires exiting from one
of the pairs of slots on the side. After the speaker and wires are in place,
seal around the top edge and in the three sets of speaker wire slots---including
the slots where the speaker wires exit.
I applied clear silicon sealant using a toothpick to seal the speaker in
Allow the sealant to dry before
installing the speaker on the chassis.
To mount the speaker over the rear truck on the chassis, you will need to build
and install a pair of shims. These shims will support the speaker above the rear
bolster, as well as leaving plenty of room for the pick up wires and the wires
running from the back-up light to the decoder. You can go ahead with installing
the shims while the speaker sealant is drying.
First cut 4 pieces of Evergreen 0.080” x 0.080” styrene strip (Evergreen PN164).
Each piece should measure about 1 ¼” in length.
Next, glue together the styrene pieces, one set of two pieces for each side of
the chassis, using a liquid plastic cement such as Plastruct Plastic Weld.
NOTE: The pieces for the
engineer’s side where the backup light is located may need to be shortened a
little to fit.
After moving any wires out of the way, glue the shims to each side of the
chassis. For this purpose, I used a
thin layer of a product called Plasti-Dip (Home Hardware), but silicon sealant
or connector coating would also work. (I also use Plasti-Dip as a connector
After the sealant on the speaker has dried, it is time to install the speaker to
the chassis. Simply tuck the pickup and rear light wires out of the way, and
glue the speaker assembly to the shims
with the speaker wires facing the decoder.
Again, I used a thin layer of the Plasti-Dip for this purpose. It dries
in an hour or two depending on temperature and humidity.
After the speaker is solidly in place, then only a few steps remain.
Cut the speaker wires to length and solder them together. Then, slide
those two insulation tubes over the solder joints and heat them with your
soldering iron until they are melted in place. Finally, tuck the wires down to
the top of the chassis where the original speaker had been located.
Below are some photos of the completed project, shown before taping the speaker
wires to the chassis.
You may wish to test the chassis with the new speaker to make sure it is working
properly. Wear ear plugs! Test the
back-up light as well to ensure it operates, too (Function 12).
all you have to do is wiggle the shell back onto the chassis and install your
couplers. Just don’t forget to reinstall those side railings!
It’s that easy.
You may find that your new speaker does come close to rattling the windows in
your layout room. I certainly had to lower the volume on mine after testing to
ensure it didn’t blast my friends during operating sessions.
We tested my Rapido FPA-4 with the newly installed speaker next to an FPA-4 with
the original speaker. Quality of sound is certainly a subjective issue, but in
my view the MLW rumbles that emanate from my locomotive are certainly very rich