The first thing the controller must do is reduce the ‘mains’ voltage (usually 240 volts AC) to a safe and usable lower voltage of 16 volts AC.
This lower voltage is now adjusted according to which system is being used to control the speed and direction of the locomotive.
Before we start with track wiring lets first refer to the locomotives and what supply they need to run. This section will refer to RTR (ready to run) locomotives manufactured by the major manufactured like
Bachmann
Graham Farish
Dapol
Hornby
Locomotives are powered by electric motors which require a DC (direct current) supply to the wheels via the track. The speed is controlled by an increase or decrease of voltage to the track and the direction is controlled by the polarity of the DC supply; for example the ‘+’ and ‘-‘ connections to the track are reversed. The voltage and direction of travel are controlled by controllers available from many manufacture.
Now we must move on to the wiring difference between DC and DCC controls because this will effect how you wire the layout. Although both systems have locomotives with DC motors the main difference is as below.
Analogue control (DC)
The 16 volts supply is changed from AC to DC within the controller together with the speed. Using the system you are controlling the track so all locomotives on the track connected to the controller will move in both speed and direction the same. (see right)
So, if you want to be able to pick and control a single locomotive you will need to devide the track into sections so sections can be switched on and off as you select the locomotive to be controlled.
See below for an example of wiring for DC control with section switches.
Digital Controls
This system known as DCC (Digital Command Control) has been available for several years now and is proving popular but again does not suit everybody who has already got a model railway. The track has a 16 volt AC supply all the time and the control system address each loco via a chip fitted in each loco. It is the chip in each loco which feeds any voltage from 0 to 12 volts direct to the motor in the loco.
One major difference between analogue and digital is because DCC loco run on a constant 16volts.
THE AC IS FEED FROM THE DCC CONTROLLER
All running tracks must be wired together to ensure where ever the loco is on the layout when the DCC controller tries to ‘address’ the chips in all loco’s only the one with the number you ‘addressed’ will move. All the others will NOT move because they have a different code number.
To enable locomotives (anything that has a motor inside) to run on a DCC layout it must have a DCC ‘chip’ fitted inside. If it is a new or fairly new it may have a socket where the plug can plug in. If old it will have to have one ‘wired in’ as shown on the video on the left.
We wish to acknowledge and thank ‘Barnabas Junction’ for this great video.
Above is a very good video on how to fit a DCC chip with sound (known as TTS) to a Lima class 20.
The cable harness refered to in above video is Part Code 860003 available mail order from LAISDCC and known as “8 pin NEM 652 socket harness
Once again we must acknowledge and thank ‘Barnabas Junction’ for the very detailed instruction.
Above is a very good video on how to fit a DCC chip with sound (known as TTS) to a Lima class 20.
The cable harness refered to above video is Part Code 860003 available mail order from LAISDCC and known as “8 pin NEM 652 socket harness
Once again we must acknowledge and thank ‘Barnabas Junction’ for the very detailed instruction.
If you plan to have a return loop where the train runs round a loop and returns back down the same track (see image on right) and you are using DCC controls this is a very useful piece of equipment made by Hornby part code R8238 seen on left.
Other makes are available so ask in your local model shop or go ‘on-line’
GENERAL WIRING
Wiring your layout is in-fact fairly basic with most of it being low voltage and current so safe to work with. You will find that much of the work is repedative, for example, wiring from point switches to point motors is the same circuit over and over again. When wiring point motors we recommend a larger size of wire because of the current required to operate a point motor coil and reduce volts drop; resulting in poor operation.
As most of the wiring is under the baseboard it is advisable to wear protective glasses when working under the board because of off cuts of wire and even solder could fall on you causing a great danger to your eyes and face. A good light source is also a good help.
The unit on the right is very usefull to confirm the supply is reaching the track.
When the supply is DC the light changes colour from red to green as the supply is reversed.
When the supply is DCC the remains the same colour but does in both cases confirm the supply is reaching the track.
If you are installing or have installed a control desk and want indicators for showing the position of point blades have a look at the diagram on the right.
A Peco twin microswitch assembly has been added to the point motor which does two things.
Switches the feed to the live frog switch
Changes the indicators onthe control panel showing the direction of travel on the point.