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Track Configuration Library (TCL)


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Track Configuration Library (TCL)



1. What is the TCL?

As a train moves down the track, it will leave one signal block and enter another.  At these points of change, signals are placed for regulation of train speed and movements. Where one signal block ends and another begins, there are a finite number of possible track arrangements.  These will range from a single track main line to a very complex interlocking.   The TCL is a reference for some of the more frequently used track arrangements or configurations that you may have on your layout.  The TCL will show the track layout with the appropriate signals.  Then TCL will show the corresponding circuit board configuration for that track configuration.  It is a reference source for the installation of the electronic part of the Atlas 21st Century Signal System and the Custom Signals Modular Signal System.  It allows the user to take a TCL configuration and use it for a similar configuration on their own layout.   Start with a simple track arrangement on your layout and follow the instructions below.

2. What needs to be done before you use the TCL?

It is assumed that you have done a Signal Layout Design Plan of you train layout with the following:

a. Identified and numbered each signal block. 

b. You know which signal model goes in each location.

c. Identified each target on each signal with the number for the block it is protecting and the direction of train travel it faces.  For example, a target at the beginning of block 3 for a westbound train would be numbered as 3W.  Two or more targets approaching the same signal block from the same direction will be labeled as 3W, 3WD (diverging), 3WX (extra), 3WY, etc.

d. Identify each turnout (switch) with a capital letter. (swA, swB, etc.)

If you are not sure of how to do all of this, it may be helpful for you to look through the TCL to see examples.  You may also check out PLANING in the Signal System section for more information. You may also contact Custom Signals to have a Signal Plan done for you at a small cost.


The TCL is made up of two schematics for each track configuration:


2. CORRESPONDING circuit board configuration FOR THAT PLAN

To begin, start at the beginning of a signal block. Then: 

a. Search through the list of track configurations until you find the one that is the same or similar to the part of the layout you are trying to signal.  You will find many different track configurations used in prototypical and model railroading.   Print a copy of the track configuration that best resembles that part of your layout.  Please refer to the C1 Scissors Crossover as an example.

b. Each of these will have the sample signal track blocks numbered.  Write your TRACK BLOCK NUMBERS on the signal layout plan next to the existing block numbers on the plan.  You need to keep both the original numbers and your own numbers so that you can reference your track blocks to the track blocks on the TCL.  You may want to use a different color pen to help distinguish your numbers.   Again, do not erase the existing numbers because you will need them for further references.

c. Each signal target in the TCL protecting those blocks will also be numbered for the block it is protecting and the direction of train travel the signal faces.  Write your SIGNAL TARGET HEAD NUMBERS from your signal layout plan next to the sample signal target head numbers on the TCL so that they correspond to the signal blocks on your layout.  The only thing that will change is the number.  Again, you may cross out the originals, but do not cover them up.  You may also want to use your colored pen for this.

d. Write the TURNOUT LETTERS from your signal layout plan next to the sample turnout letters on the TCL.  If your turnouts are already numbered, you may use those numbers.

e. You should now have the track layout written with your TRACK BLOCK NUMBERS, SIGNAL TARGET HEAD NUMBERS and TURNOUT LETTERS.   You will need this for the Circuit Board part and you should keep this as a reference for future work. 

f. Find and print out the circuit board configuration that corresponds to the track configuration found in Part a above.  Here is the Circuit Board Configuration for the C1 Scissors Crossover as an example.

g. Find the sample signal head target numbers in the J3 boxes for each circuit board.  Each of these target numbers corresponds to one of the SIGNAL HEAD TARGET NUMBERS on the sample signal plan.  Write your signal target numbers next to the corresponding numbers on the circuit board configuration. You can match them up using the original numbers.  Again, you may want to use your different color pen.

h. The TRACK BLOCK NUMBERS indicate which block will be used for detection for each SCB.  The detection number goes next to the Din on each PCB.  Next, write the new detection numbers (Din) next to the existing detection numbers for each printed circuit board.   The new detection number will be the same as the new signal block number in the J3 box from Part g.

i. Next, write your SW TURNOUT LETTER from your plan on the corresponding TSC board on the Circuit Board Configuration. 

j. Finally, change the TRACK BLOCK NUMBERS to the corresponding block numbers from your signal plan. 

This completes the modification for this track configuration.  You now have the correct Circuit Board Configuration with your TRACK BLOCK NUMBERS, SIGNAL TARGET NUMBERS and TURNOUT LETTERS for this part of the layout.

k. Move down the layout to the end of the next signal block.  Repeat steps a-j for the next track configuration.  Again, you are simply replacing the numbers and letters in the TCL with the numbers and letters from your layout plan. 

Place the new pages next to the first set of pages in the same order as your track layout. 

Repeat this process for each part of your layout moving down the tracks.  Arrange and tape together the track configurations as you print them out to form a diagram of your layout.  Also layout the corresponding circuit board configurations side by side and tape them together to form a circuit board layout.   You now have the correct circuit board layout with your signal numbers ready for mounting the circuit boards and making the connections.  If you can't find the track configuration you are looking for, call Custom Signal for assistance.

Below is a finished plan.


1. Planning and Mounting the PCBs.

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.  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 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 BSC-1s and the TSC-1s will go on the panel board.  I have provided a 4 position X 12 position diagram below which is based on my 1 X 3 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-1 and TSC-1 controllers for your layout. Again, notice that the westbound BSC-1s in the 1st and 3rd rows and some of the TSC-1s are rotated 180 degrees before mounting. You should drill 3/8î 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 for the C1 Scissors Crossover.

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

2. Connection Instructions

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. l Signal Block Detection

Step 4. Turnout Indication

Step 5. Approach ON/OFF Switch

Step 6.  Ain Common Approach Lighting

Step 7.  Interconnections from J1 to J2

Step 8. This is how this circuit board configuration will be presented in the Track Configuration Library showing all the connections.

You should test you panel board using some spare signals and a wire attached to any common terminal.  Test the Din and SW connections to see if the signals change aspects.  Once testing is completed, mount the PPB under or near the layout.

Step 9. Target Lights. Using modular extension wires, connect the target lights from the signals to the corresponding J3 socket on the signal control board.

Step 10 Attach the detection wire from each signal block back to the screw-down Euro terminals on the PPB.

Step 11 Attach the SW wires from each of the turnout indicators back to the screw-down terminals on the PPB.

In the photo below, you can see the:

1. turnout connections on the top left using orange wire. 

2. block detector wires on the top right using green wire. 

3. power and common outputs next to the detection wires. 

4. power and common inputs on the bottom right. 

5. red power on/off switch on the bottom right

6. black approach lighting on/off switch next to the power switch. 

7. white modular wires connecting the J1 to J2 connections (black sockets) on each PCB.  I route these under the PCBs where possible.

8. hard wires connecting each PCB routed through the holes under the PPB.


The Custom Signals' Track Configuration Library is for the dual use of selling or installing the Custom Signals' Modular Signaling System. Any unauthorized reproduction, distribution, modification or exhibition, without written permission from Custom Signals, is strictly prohibited.

Library A - Single Track Configurations

Library B - Double Track Configurations

Library C - Double Crossover Configurations

Library D- Triple Track Configurations

Library E - Four Track Configurations

Library F - Yard Configurations

Library G - Custom Configurations


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