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WIRING AND DCC


Wiring and DCC

introduction
fitting light and sound
resistor calculator
baseboard wiring
lighting

Again, we have gone DCC and for the most part, use Digitrax equipment. The simple operation will again be automated. The advantages of DCC are explained here. Again, we thank Malcolm Alberry and DCC Supplies help in the automation.

fitting lights and sound to an L&B train
(or how we got chuffed by DCC Supplies)
 

Bratton Fleming will display as both a day and night scene, so train and building lighting is necessary. In addition, this time, we wished to include discrete on board sound. This is when DCC Supplies came to the rescue.

 
 
The Lynton and Barnstaple Manning Wardles are the 'sausage dogs' of the narrow gauge world. I have always loved them but they are not to everybody's taste. When the railway was scheduled to be closed, Captain Howey, later of the Romney Hythe and Dymchurch fame, visited the line with the thought of saving it. He took one look at the 'ridiculous engines' and walked away!
 
There are enough issues just to fit the motor into the engine along with a very small DCC chip (Digitrax DZ125). The cab is not compromised in the new locomotives being built for this layout and I suppose it would have been possible to fit the sound chip and speaker in there but it is nice to have full cab detailing. The side tanks cannot be used for electronics as they have to be filled with lead in order to obtain sufficient adhesion for the locos to haul trains.
 

the anatomy of a sausage dog
 
Locos are united with 'companion cars' in order to enjoy more available wheels, for current collection. The obvious place to install sound is, of course, the companion car.
 
Our trains only have one side ever visible. This has enabled us to open up the doors in the guards compartment to 'let out the sound' of the installed speaker on the blind side of the companion coach. The open apertures were re-enforced by thin strips.

As the carriages are also going to be lit, all holes in the floors have been sealed off to prevent light leakage.
 

The two new brake cars with guards doors opened up for sound

the first of the coaches nearing completion
 
Equipment
 
So let us look at the general wiring requirement. One pair of wires between stock of this small scale is about all one can manage as the bending resistance of any more will derail the stock on curves. As it is, companion cars have to be quite heavily ballasted to prevent this happening.
 
The main chip, a Digitrax DZ125 remains in the loco. This will also operate the loco light, using function 0. The companion car also picks up track current and this is passed through to the loco using thin flexible wire supplied by DCC Supplies and micro connectors from Express Models.
 
To be able to switch on and off the carriage lights and rear lamp on the coaches, an additional chip is required. This is a Digitrax TL1 single function chip. This is very low cost luckily. Power for this is taken from the carriage track power pickups. The chip is set to the same address as the main chip and function 0 will be read, thus switching on and off the carriage lights and rear lamp when required. As delivered, the TL1 needs a little programming. The loco address has to be set for the required train, and to switch the lights on and off with function 0, CV 61 has to be set to 1.
 
The TL1 needs to be removable for programming as the sound chip and the TL1 have some programming incompatibility. I used Express Models micro connectors to do this.
 
Fitting instructions for the TL1 can be found here. The capacitors have a silver flash which is alongside the negative contact. The common wire should be connected to the positive side of the capacitor.
 

wiring schematic - click on image to enlarge
 
loco and carriage lamps
 
DCC Concepts in OZ produce tiny working loco lamps. In the UK, they are supplied by DCC Supplies but at over 31 for six, they are definitely not cheap. We have found the red lights seem to be very effective but we have found the white lamps put out a rather blue light. This can be 'tuned' but using a yellow varnish over the optic. In addition, the lamps are too small for L&B locos, so they must be fitted inside the correct shaped lamp.
 
The wires of these lamps are very fine indeed and require careful handling. They are in fact so fine, that in many cases, they need not be hidden.
 
 
 
The carriage lighting uses warm white sub-miniature lighthouse LEDs, again from DCC Supplies. These are soldered to a couple of brass wire bus bars which are glued onto the top of the coach cross partitions. Short lengths of heat shrink sleeves are used to insulate the brass bus bars from the metal partitions. It is important to use the correct resistors to ensure that the carriage light intensity is correct. I have found that 6 to 9Kohm resistors are ideal for us. If one coach has less LEDs than another, it is necessary to add an additional resistor so that the coach lighting intensity is equal.
 

coach fitted with lighting
 

only some of the coach lighting is installed at this point
 
Of course, when wiring the connection from one coach to the next, it is important that the polarity is correct for the LEDs to operate.
 
DCC Supplies
 
Once the donkey work had been completed, it was time to trolley off to DCC Supplies; fortunately very close by to us, just outside Worcester. The company resides in what must be one of the most pleasant business parks north of Watford. Nestling amid pine trees, meadows, a recreational lake and a small caravan park, husband and wife team Andy and Fiona have recently moved into a most spacious and well presented premises. The company is quickly enlarging its stock of model makers materials and is well worth a visit.
 

Andy and Fiona DCC!
 
Fiona tramples over all the usual  stereotypes of females and models railways... she actually knows a lot about them and is herself an expert on DCC operation. While Andy got to work fitting the function chip, Fiona programmed the sound chip.
 

Working on 009 stock is like being a keyhole surgeon. Andy always pulls that face when working on my rolling stock!
 

Fiona finally persuaded the sound chip to be a steam engine rather than a diesel!
 
It was not long before everything was neatly installed in the baggage car. I am amazed at how small the loud speaker actually is. It belts out a fair bit of volume too! Andy also installed a capacitor between the two lighting wires which stops flickering lights on bad bits of track.
 

the completed installation  - click on image to enlarge
 
After very little hassle, the train was chuffing along the test track... see the video here.
 
There was still some programming to do. This included assigning the required sounds to the specified function numbers. One will be a guards whistle which can be added to the chip. The chuffs also need to be adjusted so that there is the correct 2 per wheel revolution.  The sound of draincocks can be added for starting and the occasional safety valve blow off when stopped. Programming of the chip, and even the loading of your custom sounds is actually done through contact with the rails.
 
On returning home, the train was quickly railed onto County Gate where it happily chuffed around. Our neighbours arrived quite quickly to watch and the general consensus was that the effect is a rip roaring success.
 
Following a second visit by Fiona of DCC Supplies both trains have now been programmed to work correctly. Our own choice of whistle sounds were loaded into the chip.
 
The number of chuffs per revolution was adjusted as indeed was the volume.
 
To programme this chip, a fancy circuit board is needed along with a good understanding of computers. There are three volume levels for the main sound, (the chuff). In addition, other sounds can be added to the chuff, such as braking, draincocks and pumps.
 
Additional sounds are actuated by function switches. There is no volume control for the function switch sounds so this has to be adjusted before loading into the chip. The sounds have to be in mono. Audacity is the perfect programme to do all of this.
 
It can take quite a few minutes to load the sound to the chip and then the result has to be tested. It took the best part of a day before we were happy with the results.
 
The result is convincing and excellent. It is important to maintain the sound levels correct for viewing distance and scale. Only too often, I see the sounds being played far too loud.
 
Our thanks again go to DCC Supplies and DCC Concepts.

resistor calculator

I include this resource as it is so much easier to choose the correct resistor with this method.

baseboard wiring

This layout has very simple wiring compared with County Gate. There are only two operating turnouts, (the siding to the goods shed is snow covered and will not work), and three blocks.


click on  chosen baseboard for wiring diagram


this is how the track layout looks like on the Railroad & Co software

 
the wiring installation almost complete - click on image to enlarge


click on image to enlarge

Lighting

I have long been impressed with how awful the light is from low energy bulbs. They therefore seem the obvious choice to illuminate Bratton Fleming, which is being depicted on a dull winter's day. I am using ten GU5 . 3 'blue white' 12 volt LED spots. These put out a harsh blue white light that perfectly lights the snow and even makes you feel cold!. They are connected to a dimmer so we can obtain nightfall when required. The lights are set into holes cut into the plywood and are lightly glued in place with epoxy. This is possible with LEDs because they run cool but such a system would cause a fire with halogen spots!

In addition, we use an LED strip of blue white light which we focus onto the backdrop to remove shadows.


the baseboard inverted and the half the LEDs already installed - click in image to enlarge

Another line of blue LEDs are installed for night light.  These are also connected to a dimmer.


N95CC 220V to 12DC 6amp (good for four GU5 LEDs)  size, approx 50mm X 35mm X 35mm

The 4 Maplin transformers are wired together in parallel to produce sufficient power for the lights. There are two potential 12VDC feeds on each transformer, each marked 0 and 12V. If you require the full output, the 12V tags must be joined together and likewise for the 0 tags. The dimmers were supplied by DCC Supplies.