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An oval test track was designed to test all the Lay Command and Control,  LCC, signal and automation electronics and software before starting a much larger layout. Layout Command Control, LCC, is a NMRA standard protocol for layout automation.  This is a link to several presentations  This is a link to NMRA LCC documentation  This is a link to an LCC discussion group  Dana Zimmerli authored Introduction to Layout Command Control: Basic Concepts and Practical Examples of LCC for Model Railroads. Train Controller Gold is the automation software.  (It was chosen after discussions with a professional model train layout designer and installer.)  The oval test track with sidings as shown in Fig. 1.

Test Track

Fig,1. LCC signal, block detection and Train Controller automation test track.


B-Block, example: B”1”-Block 1, B1”A”-Block 1 detection section A.

M-Signal Mast, M”C”-Clockwize signal, M”R”-Reverse Clockwise signal, M”D”-               Clockwise Turnout signal, M”T”-Reverse Clockwise Turnout Signal, example: MC”1”- Clockwise signal Block 1.

TO-Turnout, example: TO”2”-Turnout Block “2”.

I described my layout vision here  It will take 4-8 months to complete all the hardware and software development.  It will be easier to describe and document the work along the way.

The design choices were made taking cost, technical capabilities, my time and the joy of learning into account.  Even before the test track was built a simulator of the test track was built and tested.  The test simulator will be described in this topic.  The test track uses a basic Automatic Block Signaling, ABS, system.  Three aspect masts are used on the mainlines. The red stop aspect indicates that the next block is obstructed, yellow approach speed aspect indicates an obstruction in the block after the next and the green clear speed aspect indicates no obstruction to be expected. Two aspect masts are used for the siding.  The red stop aspect indicates the siding is obstructed and the yellow approach speed aspect means proceed onto the siding or off the siding onto the mainline.  The LCC logic is capable of implementing very complex block signaling systems.  Several HO layouts have implemented more complex signaling of the railroad they are modeling.  The LCC network contained three RR-CirKits Signal LCC nodes, RR-Cirkits LCC-LocoNet Gateway, RR-Cirkits LocoNet USB Buffer, RR-Cirkits Power-Point (May have trademark problems ), my design ESP32 LCC 18-Input node and my design ESP32 LCC 16-Output node.  My ESP32 LCC nodes with MRNLite open source software are about 84% less per simple I/O than RR-CirKits.  The RR-CirKits nodes are used for the infrastructure and the more complex logic needed for track signals.  The ESP32 LCC 18- Input and ESP32 LCC 16-Output are shown in Fig 2.

ESP32 LCC Nodes

Fig. 2 ESP32 LCC 18-Input and ESP32 LCC 16-Out are on the Left and Right respectively.

The LCC network is implemented using the CAN bus over ethernet cabling.  The ESP32 LCC 18-Input is shown with three 6-channel block occupancy detectors (3-rail) in Fig 3.  The 6-channel block occupancy detectors are based on a design by Professor Chaos,

Block Detection

Fig. 3 ESP32 LCC 18-Input node connected to 3 6-channel block occupancy detectors.

The RR-CirKits LCC Signal Nodes,  RR-Cirkits LCC-LocoNet Gateway, RR-Cirkits LocoNet USB Buffer, RR-Cirkits Power-Point are shown in Fig 4.  The LCC-LocoNet Gateway and LocoNet USB Buffer are required to communicate with Train Controller.  Only a USB-LCC Buffer is required to communicate with JMRI or stand alone.


Fig. 4 RR-CirKits LCC Signal, LCC-LocoNet Gateway, LocoNet USB Buffer and Power-Point.

To reduce cost a 3 aspect mast LED driver board was designed to use only the red and green outputs from the RR-CirKit LCC Signal node to generate the yellow output (When there is no red or green output a yellow output is generated).  A CMOS 4 channel 3 aspect mast LED driver board is shown in Fig 5.  A TTL version was also developed.

IMG_0887 [2)

Fig 5. A 4 channel 3 aspect mast LED driver board (CMOS version)

A red or green aspect signal generated by the RR-CirKits LCC Signal node costs about $4 and a yellow aspect signal generated from the red and green signals cost about $0.50.  To reduce cost a 2 aspect mast LED driver board was designed to use only the red output from the RR-CirKit LCC Signal node to generate the yellow output (When there is no red output a yellow output is generated).  The CMOS 8 channel 2 aspect mast LED driver board is shown in Fig 6.  A TTL version was also developed.

IMG_0887 [3)

Fig 6. A CMOS 8 channel 2 aspect mast LED driver board

All the components used in the test track simulation before wiring are shown in Fig 7.  The RR-CirKits LCC-USB Buffer is shown instead of the LCC-LocoNet Gateway and LocoNet USB Buffer.  There are 3 sets of slide switches to emulate track section occupancy. There are 3 boards with LEDs simulating the 12 x 3 aspect masts, a board with LEDs simulating the 8 x 2 aspect masts and a board with LEDs simulating the position of the turnouts. A push button board is used to set the position of the turnouts.


Fig 7.  The test track electronic components.

The wired test track simulator with no mainline obstructions is shown in Fig 8.

Test Track Simulator

Fig 8. Wired test track simulator with no mainline obstructions.

Unfortunately, the red LEDs look yellow to my iPhone.  Figures 9a, 9b, 9c and 9d show the labeled slide switches for block occupancy, LED boards for the 12 x 3 aspect masts, the LED board for the 8 x 2 aspect masts and LED board for the turnout position and the push button turnout control board, respectively.

IMG_0925 [2)

Fig 9a. Block occupancy slide switches

IMG_0927 [2)

Fig 9b. 12 x 3 aspect mast LEDs

IMG_0928 [2)

Fig 9c. 8 x 2 aspect mast LEDs


Fig 9d. 4 push button turnout controllers.

Video 1 shows test track simulator (repeat of the photos)

Video 1. The test track simulator

Video 2 shows the test track simulator when different turnouts are thrown.

Video 2. Turnouts changing on the test track simulator.

Video 3 shows the test track simulator with various block occupancies and turnout positions.

Video 3. Test track simulating block occupancies.

The LCC test track simulator worked correctly for all the different configurations tested.  LCC can be the lowest cost, most flexible and largest scalable block signal system available to model train layout hobbyists.  Later this week, grandkids permitting, I will continue the post showing videos of Train Controller working with the LCC test track simulator and TMCC.  When I return from the lake I will build Professor Chaos’s Legacy to DCS Bridge and use it with Train Controller,  This will allow the Train Controller to automate both TMCC and DCS engines.   I will also post the incremental cost per mast calculation.  My initial cost goal was $5 but the use of the RR-CirKits LCC Signal nodes raised the goal to $12 per mast. (I didn’t want to develop and test the complex signal logic. A my time versus cost decision.)


Images (12)
  • Test Track
  • ESP32 LCC Nodes
  • Block Detection
  • RR-CirKits
  • IMG_0887 (2)
  • IMG_0887 (3)
  • Componets
  • Test Track Simulator
  • IMG_0925 (2): Fig 9a. Block occupancy slide switches
  • IMG_0927 (2)
  • IMG_0928 (2)
  • IMG_0926
Videos (3)
Last edited by carl552
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Cost per Block Signal

These tables show the incremental cost of different types of block signals and track occupancy detection.  There is the over head cost of the RR-CirKits start up kit, computer, wiring, connectors and a 3D printer.  The computer and 3D printer have many other uses.  There are four block signal designs, a signal 3 aspect mast, a back to back dual 3 aspect masts, a 3 over 2 aspect mast and a 2 aspect dwarf signal.  The first table shows the incremental material cost of the four block signals.  The nominal 3 aspect block signal incremental cost is $10.72.  The 2 aspect dwarf signal incremental cost is $5.99.  The 3 aspect back to back block signals incremental cost is $19.68.  The 3 over 2 aspect block signal incremental cost is $15.51.  The occupancy detection was not included in the signal costs because it was developed for the train automation.  The incremental cost of a single occupancy detector is $0.97.  First table shows the total incremental costs of a sensor and block signals.

0001 [2)

Table 1.  The total incremental costs of the occupancy detection and block signals.

The cost breakout of each item in Table 1 is shown in Table 2.

Cost11024_1 [2)

Cost21024_1 [2)

The LCC network allows hobbyist to design and build small to large and simple to complex automated layouts with block signals.  The hobbyist can choose their cost/labor trade-offs with buying the all the components to building many themselves.


Images (3)
  • 0001 (2)
  • Cost21024_1 (2)
  • Cost11024_1 (2)


Very interesting design, do you mind sharing some details?

Where did you get your 3D design for the signals? Can you post a picture of them? Your cost is very attractive, these are typically the highest cost component.

What does your ESP32 LCC Input & Output boards do? I assume they put the digital I/O on the LCC network. Did you write the LCC code for the ESP32? I would like to add LCC to my design but I find the documentation for implementing the code to be impossible to decipher.

Where is the ABS logic implemented? How extensive is that code?

You mention Train Controller Gold, have you started using it yet? A review of it and how well it works would be great.

Thanks for posting your progress.


I designed and 3-D printed the block signals.  Here is my post

My ESP32 LCC Input monitors 16 3.3V input lines (Mostly used to monitor and report the block detection circuits).  My ESP32 LCC Output node has 16 3.3V outputs.  (Mostly used to control 10A relays that can be used for accessories and switch motors).  I modify the mrnlite library for the I/O nodes.


The ABS logic is implemented by the rr-cirkits Signal LCC.  The signal coding in the Signal LCC is very flexible and can be simple ABS or quite complex.  There is a learning curve to using the Signal LCC.  Best to buy and read Dana Zimmerli's book on using LCC.

So far I have been impressed by Train Controller.  Dave Hikel recommended it to me.


Hello Sir I'm sorry to bother you I would like to know if this Concept can be used on O-Gauge Layouts using Lionel Fastrak? My Layout runs mainly on a Conventional Postwar system and soon will be including Legacy.

Can your Automated Block Signal System be Incorporated with my Postwar and Legacy System? Do you have a Video that explains how your System Works? If you don't have one Do you think you could make a Video showing us how this works Please.

Thank you for your time



Hi Allan,

Yes, you can use LCC with Postwar, Legacy or DCS.  It is for layout control and automation and is independent of engine control so it can be used with any system including conventional.

A big challenge is to get block detection on all of your layout.  A good discussion of block detection

There are many LCC videos on Youtube.  Most are better than what I could do.

Join and the layoutcommandcontrol group.  A good LCC discussion and help group

Hi Jonathan,

The documentation is in the sketch comments.  MRNLite only does LCC input and output so the program concept is fairly simple.  This is the path I took to understand and build LCC nodes with the ESP32.

1. I purchased and completed the ESP32 tutorial from Random Nerds Tutorials and an ESP32 development board

2. Watched several LCC videos

3.  joined and the Layoutcommandcontrol group and the openlcb group.  The openlcb group deals with the programing of the LCC nodes.

4. Buy and play with the RR-Cirkits starter kit and Signal LCC node.

5. Read Dana Zimmerli's book

6. Designed and built the LCC Input and LCC Output nodes with ESP32.  I did not want to design and build a comparable Signal LCC because of the software complexities.

7. Demonstrate my LCC Input and Output nodes working with rr-cirkits startup kit and Signal LCC node.

The DipTrace PCB design files for the ESP32 Input and Output nodes are attached.


LCC ET Node18v5 - LCC Input Node

AccessoryAC16v4 - LCC Output Node


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