Consolidation - rewiring for better performance

Why am I doing this?

  1. I want a better speaker
  2. The number boards and classification lights go on and off with the headlights
  3. I don't like having all the high amperage wiring going from the loco to the tender and back
  4. I like the ability to have the loco run without the tender
  5. There aren't enough wires between the loco and tender to support the lighting properly.

If you read my review on the main Consolidation page, you will see that the headlight, marker lights and cab lights are all on the same circuit. There is no way to separate them because all 8 wires are used up.


If I rewire the loco and put the DCC decoder in the boiler (where there is plenty of room.) then the 8 wires can be:

1 & 2 track pickup

3 & 4 speaker

5 & 6 rear headlight

7 & 8 possible switch for smoke or other feature like remote controlled coupler

Also the wiring simplifies since I want a second speaker in the smokebox, like a tweeter to make the chuff sound like it's coming from the smoke stack, not the coal load!

Tender modifications:

A final look at "before". Notice that there is no room for a good speaker either!

First step: prepare the tender

Dissassemble the tender, there are 6 scres underneath.

Unscrew the voltage regulator that is screwed to one of the weight stacks. Unscrew the 4 screws holding the circuit board, and unscrew the 4 screws and the remove the clips holding the speaker.

Now unsolder the 8 wires from the connector to the loco, and the pickup wires from the trucks. Also remove the weights and fish out the "battery power" plug that sticks out the end of the tender.

Next, use a dremel to cut off the 4 standoffs, and the ring that is above the floor. I used a large cutoff wheel parallel to the floor.

I then cut out the holes under the speaker, to let more sound out... just be careful not to cut into the brake gear.

In the picture above, you can see that I have sliced off the 4 posts that held the circuit board, and the raised ring around it.

I've also cut out the areas with the small holes, it just blocks too much sound. I'll finish the opening smoother later, just for aethetics, but this is good enough.

Again, cut carefully and you will not damage the brake gear below.

I found a nice big 3.5" speaker from litchfield station, SP-92SHP-06, the speaker is 3.37", outside frame is 3.6" and 2" tall (the litchfield station sizes are wrong).

Next: mount the speaker, solder up wires:

Note: I added 2 connectors, one for the rear light and one for the number boards. The number boards are tied to the track pickups, so the run from the track and are on all the time. Since I run DCC, there is a full wave bridge and a 20 ma current regulator.

Before buttoning up the tender, I added some foam inside to minimize echos.

Tender Lighting

I changed the

I also found some buzzing from the tender at high volumes. It's the coal load vibrating in the shell. Since it's easy to open with the 6 screws and the decoder is not there anyway, I silicon sealed the coal load in place, lay down a bead in the ledge on 3 sides of the tender shell, and put a bead on the 3 sides of the angled end of the coal load. After installing, then ren a bead inside and smooth with your finger.

Locomotive mods

Now to figure out how to rewire without tearing up the circuit board on the end of the motor. If you remove the white goop on the connector wires at the board, you can see that pin 1 is identified by a square land on the circuit board, all the others are round. It's also on the fireman's side.


1 - smoke unit black wire

2 - smoke unit red wire

3 - cab light black (also connected to headlight and classification lights)

4 - cab light red

5 - motor minus

6-  motor plus

7 - track left (firemans) side

8 - track right (engineers) side


So, I will solder 4 wires to the circuit board attached to the motor, 2 wires to the upper "blobs" where the track pickup wires come from the motor block, 2 wires to the blobs that connect the motor brushes.


Cut off the connector (leave enough wire to solder to later) that fed the cab light. Extend those 2 wires (pins 3 & 4) to the QSI board for the speaker.


There are 2 black wires that run to the headlight and marker lights. Cut them about 2 inches from the cab. This will leave enough to use later if needed, but the other ends will reach to the QSI board (remember you will need dropping resistors).

 for reference, the headlight and 2 classification lights draw 103 ma @ 5 volts.

the red and black wires used for the smoke unit will go back to the tender for the rear headlight

so to review:

1 & 2 will go to the tender headlight (1 minus, 2 plus/dcc common)

3 & 4 will go to the speaker in the tender

5 & 6 will not be used in the tender (still connected to motor)

7 & 8 will be connected to track pickups in the tender.


Ok, so now I know the wiring I want, wire up the loose wires in the tender. Wire the engineer side track pickups (2 wires, one each truck) to the wire from pin 8

Wire the fireman's side track pickups (2 wires, one each truck) to the wire from pin 7

Wire the speaker to the 2 wires from pins 3 & 4.

I'm modifying the light in the tender, will do constant lighting for the number boards, separate from the headlight

use pins 1&2 for the tender headlight

(the number board lights will be connected to a full wave bridge and dropping resistor from the track pickups

Below is the beginning wiring on the tender, the headlight and number boards are not connected yet (the 2 free wires are the headlight wires)


Look how much bigger the new speaker is, no way I could have gotten a quality speaker under the existing electronics:



For the locomotive, there is plenty of room in the boiler:


And the wiring is quite simple, you will see that the headlight, cab light, and backup light wiring is not done yet:


Smoke switch:


Tender lighting

Well there is a single housing for the number boards and the tender headlight. Stock, an incandescent bulb is part way in the reflector and the other half shines on the number boards.

It not only looks terrible, but the number boards are only on when the tender headlamp is on.

What I did is first get a smaller, 3mm golden white led, trim the leads short, and wire up using the original wires out the back of the housing and down through the original hole in the tender top. I aligned the pins on the led vertically, since I had plans for something else in the same space. I found a small shiny washer to control the depth of the led. To remove the old bulb, use a small drill bit and push in from the back, it will pop out the lens.


Now to the number boards. I took small surface mount LEDs, about 3mm on a side, glued to a small strip of 30 or 40 thou. styrene. Glue the LED to the very top, and now work it up into the squar hole in the bottom of the casting, from inside the tender. You will have to fiddle a bit with the strips to get them on either side of the wires for the headlight LED. The picture below shows the 2 styrene strips sticking out.


This way, the LEDs are each facing right at the number boards. It looks great. The LEDs are powered from the track, so they are always on, although if I wanted to control them separately, I could use the 2 remaining pins, but then would have to hack up the circuit board traces.



Weather Underground PWS KCACARLS78