Tools Needed:
A small soldering iron
60/40 rosin core solder
Rosin Flux
Phillips Head Screw Driver
Slot head Screw Driver
Wire cutters
Wire Strippers
A X-Acto No.151 blade and handle
Razor Saw
Dremel with cylindrical cutter and sawtooth cutter
1/8, 3/16, 3/64, 1/4 & 5/32 Drills
Rubber Cement
Clear Household glue
Silicon Caulk - DAP Silicone Ultra is a good one


Materials :
Soundtraxx Tsunami Sound Decoder
Dallee 2-pin #757 & 3 pin #758 connectors
Phosphor bronze .005 thick sheet from Clover house, brass could be substituted
.060 thick styrene sheet
Neolube
1/16x3" balsa sheet
1/16" thick printed circuit board

Dallee connectors
An X-Acto #151 3/16" chisel gouge blade for  popping the boiler off
Click here to Modify the Locomotive and Finish the Project.
(Click on Images to Enlarge)
Cut away the coal bunker in the tender shell. Leave the front mounting lug. I really like this sawtooth burr from Dremel for this work.
Speakers: There is enough room to put two 1-9/16" diameter speakers. The ones on the left are are a Philco TS19 and a Soundtraxx. I used that combo in my 2-8-0s and they worked well. I am using two Kobitone speakers from Mouser Electronics shown on the right. The tall one is #253-2015 and has a paper cone, the short one is #235-5405 with a mylar cone. I find mixing the two styles gives a better sound. I really like the #235-5405.
The tender has to be raised to be clear the connectors and a better appearance. Cut the lugs off the tender truck mounts. Make a .060 thick spacer the same diameter as the truck mount post. Glue the lugs back on by turning them upside down to use the clean face for the gluing surface. Drill out for the truck screws.
Drill two 1/2" diameter holes in a 1x4 block of wood. Space them at the truck centerlines. This will protect the tender steps while being worked on.
Remove everything from the tender deck.
Rubber Cement the template to the tender deck.
Click here for a PDF of Tender Templates
Mark the hole centerlines with a center punch.
Silicon Caulk
Use a 3/64 drill to drill out the pilot holes.
Drill out the speaker holes
Make a speaker mount from 1/16x3 balsa sheet to match the template
Locate the speaker centers and use a compass to mark the speaker holes. Make a light circle to mark the speaker location. Make a groove for the speaker hole. Cut the speaker hole out with a single edge razor blade. The balsa mount keeps the mylar speaker face above the tender floor and provides an inert surface for the speakers.
Glue the balsa mount to the tender floor. Make sure the body clears the mount.
Glue the speakers to the balsa using the silicon caulk.
The male Dallee connectors have a locking lug. Cut off the lug, the will stay without the lug.
Connect one + and - terminals of the speakers with a Dallee two pin male connector. Jump the other with a small length of wire.
Make two pieces of 1/16 thick PCB to mount the female three pin Dallee connectors. They should be 1/2" wide. I made mine a 1/2" long, they should be 7/16" long. The shorter plate will allow the harness wires to clear the balsa speaker plate. Make pads by cutting grooves in the copper coating with a razor saw. Make sure the grooves are clear by running a scriber down them. Splay the connector leads to fit on the PCB board lands. Solder the connecters to the boards and tin the far end. Clean the grooves again to make sure there is no crossover.
Glue the pads to the tender floor with ACC. The pad front is 7/16" in from the tender front. Drill 3/64" holes at the base of each pad. Cut the Decoder harness wires 1" long and thread them through the holes. I used a sequence of red, orange, blue, white, gray and black. Solder the harness wires to the pads.
Cut two slots with a razor saw about 1/4" from the truck side frame for the wipers. This slot goes through both sides of the bolster. Cut a slot as wide as the tender hook up wire about 1/16 away from the wiper slots in one side of the bolster.
Make the wipers from .005x1/16 wide sheet stock. Bend them to the configuration on the Tender Template PDF. I coat the backs of the wheels with Neolube. This makes them flat black and gives added electrical conductivity.
Solder flexible wire to the wipers. Solder the wires in between the bolster uprights. I use the wire found in non-functioning computer mice. One set should be about 4" long and the other about 1" long.
Put small dabs of silicone caulk at the wiper at the arrows.
D-OH! Don't try soldering the wipers like this, any movement of the wires will pull the wipers away for the wheels.
Solder the tender truck wires to the pads connected to the red and black harness wires. They should be the outer pads.
Paint white stripes on one harness to make one harness distinguishable from the other.
Plug the 3-pin harnesses into the plugs on the tender floor. Mark the striped harness at the connector with white and put a white spot on the tender floor.
Push the purple speaker wires onto the 2-pin female connectors. Glue the connector to the wire with a thick no-run ACC gel.
Plug the decoder into the speakers and put the tender shell onto the floor. Use the original screw and the front lug. I have found the 1-9/16 diameter speakers give enough friction to keep the shell in place. If a different speaker is used back lugs may have to be fabricated. Make a temporary foam cover for the opening. Test the sound, it should sound really good.
That finishes the tender section, go to the next page for locomotive modification.
UPDATE
Click here for an update on making connectors and the new light board