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System Design | Additional Wiring Instructions



I will take you step by step through the wiring of the printed circuit boards (PCB) installation using the C1 Double Crossover as an illustration. I STRONGLY ENCOURAGE that all of these PCBs should be mounted in a single location following the printed schematic diagrams in the TCL.  I know that this will then require home runs of the signal target wires and the detection wires back to this location, but adding additional features will become much easier and more economical in the long run.  I use #4 PH screws, 1" long and 1/2" offsets made from Evergreen #226 or Plastruct #90605, 3/16" styrene tubing as offsets for mounting the PCBs.  These are available from Custom Signals for $3.00/sq. ft. of mounting board. 

As you read through the TCL, you will notice that the 2nd and 4th rows of PCBs are generally for the eastbound signals and the 1st and 3rd rows are generally for the westbound signals.  There are some exceptions to this rule.  You may want to purchase a PREDRILLED PANEL BOARD from Custom Signals for mounting the PCBs.  It comes predrilled for placing the PCBs according to the TCL.  It also comes with the screws and offsets provided and will simplify the installation for the first time user.

Layout your schematic drawings side by side from your beginning point.  You need to layout where the BSCs and the TSCs will go on the panel board.  I have provided a 4 position X 16 position diagram below which is based on my 1 X 4 foot PREDRILLED PANEL BOARD for your use.  Each box represents the location of one of the PCBs.

Click here for a 4 box X 16 box diagram as described above.

Click here for a 8 box X 16 box diagram for larger layouts.

Use the box diagram to fill in for the BSC and TSC controllers for your layout. Again, notice that the westbound BSCs in the 1st and 3rd rows and some of the TSCs are rotated 180 degrees before mounting. You should drill 3/8 inch holes in your mounting board for passing the wires underneath the mounting board from PCB to PCB.

Click here for sample 4 box X 12 box diagram filled in as described above.

Next, attach the PCBs to your mounting board in the specified locations. Again, the Custom Signals Pre-Drilled Circuit Panel Board will make this much easier for the first time user. You will only need 2 screws per circuit board in opposite corners. The 1st and 2nd rows as well as the 3rd and 4th rows will overlap and share screws in the overlapping adjoining corners.

Once the PCBs are mounted, you may begin the hard wiring. Although it appears that there is a lot of wiring, remember that there is also a lot of information that must be communicated from board to board. Most of the bulk of this information from PCB to target and PCB to PCB is done with modular cable. This saves a lot of time considering the amount of information needed to be sent. Follow the illustration of the C1 Double Crossover as an example of how you would wire your panel board. If you have any question, please e-mail support@customsignals.com or call Custom Signals directly.

I have used the C1 Double Crossover to illustrate the wiring instructions for the PCBs. There are 8 steps to completely wire the signal system for full operation of all functions. Step 5 is optional if you do not move in and out of Approach Lighting mode. If you want it all the time, you can use the JP2 jumpers. The dotted lines represent wires that are snaked under the panel board. The connections include:

Step 1.  Power

Step 2   Common 

Step 3.  Signal Block Detection

Step 4. Turnout Indication

Step 5.  Approach ON/OFF Switch 

Step 6.  Ain Linking Approach Lighting

Step 7. Target Lights  

Step 8. Interconnections Between the PCB 

Step 9. This is how this circuit board configuration will be presented in the Track Configuration Library showing all the connections.

Below is what the final completed board will look like.


The Custom Signals’ Modular Signal System will work for both 3-rail O-Gauge trains and 2-rail in any gauge.  The only place it varies is the method of detection. 


In railroading, DETECTION is the ability to find the location of a train.  Real trains generate their power inside the engine.  In some cases they use a 3rd rail or overhead line from an outside power source.  In any case, the rails support the train, but do not power it.  The real railroads use the fact that the 2 outside rails are electrically separated (insulated) from each other with wooded or cement ties.  They use this and incorporate sophisticated electronics to detect trains and other safety related purposes.  Since their detection system is very critical, they make this as full proof a system as possible.  I will not get into that now. 


In model railroading, we may not be as lucky.  For most model railroads there is a “hot” rail and 1 or 2 “common” rails.  We not only support the train, but we must also power it through the rails.  Our detection systems do not have to be as elaborate, but we would still like to be assured that it is working properly.  Model railroad detection systems have been around for a long time.  Below are some suggestions for detection when using the signal system.


DETERMINING SIGNAL BLOCK LOCATION:  One of the first things you should do is to have a signal plan completed.  This will tell you the location of your signal blocks and the location of the signals for prototypical operation.  The placement of the signals and therefore the signals blocks is more important for prototypical operation than the location of any power blocks.  The power blocks will usually follow the signals blocks. 


In some cases, one of the rails will have to be cut at each end of the signal block to insulate it from the rest of the railroad.  If your track has not been put down yet, simply put a plastic insulating pin at the correct locations as you lay the track.  If your track is already down, use a Dremmel tool with a cutting blade to cut the insulated rail at each end of the signal block.  Fill the gap with clear silicone or Plastruct material.


Most signal blocks will be going from one turnout to another turnout.  Try to cut the rail as close to the turnout as possible.  You are trying to get an uninterrupted length of rail from one point to another point insulated from the rest of the track.  The easiest way to do this is to just eliminate the area containing the turnouts.  Keep the turnouts separated from the insulated detection sections of track used for the signal blocks.  In some 3-rail cases, the turnout manufacturer has probably connected the 2 outside rails together within the switch for continuous power.  This also makes including the switch more difficult to use for detection. 

The real railroads call the length of track between signal blocks (where the turnouts are located) the “OS” section.  It can be incorporated into the detection system if you like, but involves additional detectors for 2-rail and wiring with diodes.  Call Custom Signals for more information on wiring the OS sections.  How we recognize that a train has been detected varies from 3-rail to 2-rail.


3-Rail:  One of the big advantages of 3-rail trains is that the 2 outside rails are both used as common rails.  All other scales only require one hot rail and one common rail.  3-rail trains are no different.  I have seen the insulate rail detection system used successfully on big model railroads with both TMCC and DCS command control systems.  We can insulate one of the 2-outside rails and use it for detection just like the real railroads.  Most track manufactures (Atlas, Gargraves, Ross, etc.) know this and produce track with the 2 outside rails insulated directly from the factory.  If your track has wooden or plastic ties with no outside common rail connection underneath, your track is probably insulated.  Use an OHM meter to check this out.  If you have previously connected your 2 outside rails together, good job!  You may cut the leads under the table and use one lead for the insulated detector rail and the other stays as a common rail.  To summarize, you now have one hot rail in the center, one common rail to power the trains and one insulated rail for detection.


The Atlas Block Signal Control Board (BSC-1) has built in 3-rail detection.  Simply connect the drop lead from your insulated rail section back to the Din terminal on the Block Signal Control board with that signal block number.  You only need to run one lead back from the insulated rail then simply daisy-chain it to all the BSC boards with that signal block number.  Depending on the distance, a 24ga wire is the most you will need. 


2-Rail:  In a 2-rail system, an additional detector is necessary.  Any detector that has an “OPEN COLLECTOR OUTPUT” will work.  There are different types of detectors on the market.  These include current sensing, opto-sensor, infra-red detectors.  I carry common current sensing detectors from Atlas, NCE and Daylee Electronics.  I also carry the opto-sensing detectors from Circuitron.  Each system has its pros and cons.


CURRENT SENSING DETECTORS: All of the above 3-rail instructions must be done to obtain an insulated rail for current sensing detectors.  This time all the power for the signal block rail will go through the detector and the output from the detector will be sent back to the Din on the Signal Control Board.  Follow the manufacturers’ instructions and try to be consistent and use either the hot rail or the common rail throughout the entire layout for detection.  If you are using a separate power source, the common for the detector power source must be connected to the common for the signal power source.


PROS: The current sensing detection is usually less expensive then the other options.  In most cases, it also works better than the other methods.

CONS: It requires cutting the rails and also modifying some rolling stock with resistors wheel sets.


OPTO-SENSING DETECTORS: These use photo cells mounted under the track at specific locations.  The BD-1 detector has built in logic to detect a train entering the block from either direction to turn on the block on.  It will also turn the block off when the train leaves the block.


PROS: This does not require any cutting of the rails.  It does not require any modification of rolling stock.

CONS: This is not as accurate as current sensing detection and usually more expensive.  It will not detect a piece of rolling stock left in the block after the train leaves.  Although adjustable, it is light sensitive so operation without lights may not work. 




This section is being developed and will be up soon.


This section is being developed and will be up soon.


The DZ 1000 Switch Machine is a very reliable switch machine that can be used with many different brands of switches.  It does not come with any auxiliary contacts to do optional functions.  The DZ-1008 will give the 1000 the extra contacts necessary to do additional functions. 


Read the instruction sheet that comes with the DZ-1008 carefully.  The turnout switch that controls the DZ-1000 will be wired the same as before.  This will leave 3 additional wires, white, green and gray.  These wires would normally be used to power the lead rails on longer turnouts.


We can make use of these wires to send the “SW” turnout indication back to the Turnout Signal Control (TSC) PCB.  The Blue wire is the Common wire that will feed the other 2 wires as the turnout changes direction.  Connect the Blue wire to the common of the signal system.  3-Rail layouts can go directly to the common rail. 


The white and gray wires will alternately connect to the blue wire as the turnout changes direction.  The correct wire to use will change depending on the position and direction of the switch.  So connect either the green or the white wire back to the SW connection on the TSC.  Change the switch position and watch as the signals change indication.  If the signals are not working correctly for the track routes, move the connection to the other wire.  Check the signals again.  This should give you the correct aspects at the turnout.        


If you have any other question, please e-mail or call.



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