Northern Tablelands Express approaching Ardglen Tunnel

Northern Tablelands Express approaching Ardglen Tunnel
Click on the above photo to see the Main North Album at Flickr

Wednesday, January 11, 2017

Adding Ray Pilgrim's (Shapeways) Semaphore Signals to the Main North

Some years ago I installed a basic Colour Light signalling system on the single line from Broadmeadow as it winds up to Werris Creek, due to the 3 peninsulas restricting the operators view of what’s happening on this 40 Metre (130 feet) section of the layout, see below. The signals for the 2 blocks were controlled by NCE Occupancy Detectors, so that when the applicable section (block) is occupied, both the signals were set to Red.
During recent Operating Sessions a few Operators had asked if the Murrurundi to Werris Creek section could be further divided that would speed up train movements.

I had purchased some of Ray Pilgrim’s Shapeways 3D Semaphores available at:
and this was an ideal time to install them. I decided to divide this Murrurundi to Werris Creek section, at Pangela instead of where the Bankers disconnect at Ardglen. Furthermore Pangela is more of a central point of this block, the Loops were longer and the “crossing” procedure was easier to see, see the track plan below.

Making the Semaphores. 
Ray has provided a very comprehensive Instruction Manual to help us, at:
The Semaphores are not difficult to make but require some time and patience especially when getting the length of the .015" Phosphor Bronze Operating Rods, correct. The beauty of these Semaphores is what’s on the underside of the Signal with the 2 "screw adjustable" mechanical stops for the Signal Arms, already included on the casting. This makes adjusting the Signal Arm positions (Stops), very easy and can be done while on the bench.

Lighting the Semaphores.
I wanted to "light" my Semaphores by adding a single "pre-wired" 0.8mm Surface Mount (SMD) LED purchased from Gwydir Valley Models Part No GV31a and powered the LED by a “local” 12.0 Volt Power Pack or from the same Supply for the Octopus III. The colour of the light being achieved by painting some Microscale Kristel Kleer (or similar) into the 2 Signal Arm Lenses then painting them with Tamiya Clear Red and Green when dried, all explained in Ray's Instruction Manual.
I glued the two twisted very small wires from the LED to the rear  of the Post and terminated them onto a piece of PCB Sleeper complete with a 1,000 Ohm SMD resistor. Painting the Post conceals the fine wires to a point that they can hardly be seen.  

The below photo shows the 8 Semaphores (prior to completion and painting)

Motorizing the Semaphores. 
I used the small remote control car “9G” Servos available from the Model Railroad Craftsman, Gwydir Valley Models etc. Other methods I did not try, include Tortoises, Muscle Wire, Relays etc. 
Servos won’t operate by just supplying 12.0 Volts to them, they need a Servo Driver (electronics). The cheap cost of the small 9G Servos will offset the total cost when comparing the other options.
I used a Tam Valley Depot Octopus III, an 8 channel Servo Driver, see:
Alternatively I could have used 8 x Tam Valley Singlets (1/8 of an Octopus plus an Accessory Decoder) that is supplied with a LED Fascia Control. 
My intention was to control the Semaphores automatically when trains/locos are sensed in a Block using current Occupancy Detectors (NCE BD20s) and to initially position the Semaphores by operating the Toggle Switch for the Points so I did not need the LED Fascia Control. Better value using the Octopus III. Fascia Controllers can be purchased separately. Details on how all this works, later.

Mounting the Semaphores.
Requires a 20 or 22 mm hole depending on type of Semaphore, with the centre point, 6 HO feet from the track (23 mm). 
On my previous Colour Light signalling system, for simplicity, I mounted the Signals "outside" the Point (on the main line) but I noticed Operators stopping at the Signal without being aware that they were blocking the the oncoming train from entering the Yard/Loops. 
Installing the Semaphores has to be in the "inside" of the Points to the Yard/Loops without a stopped train blocking the "entrance", allowing trains to pass as shown below.

Operating the Semaphores.
There are many variations on how to operate Signals to as easy as using a Switch or to as complex as using a computer program like JMRI’s Panel Pro, Railroad and Co etc.
While I'm familiar with what JMRI’s Panel Pro has to offer, I did not need the complexity and further expansion capability at this stage and more importantly I did not want to spend the time learning how to do/use it, at least not right now. A job for "ron", much later 'on.
Previously I had used a NCE Mini Panel for an automated train control test and thought I’d be able to use it to tie all the Signals and occupancy together but this required the Octopus III to be “DCCed” using the Tam Valley Octocoder. Subsequent testing we found the Octocoder had timing issue when using Macros, a common method of operating multiple Accessory Decoders. With this issue and not being able to get the first part of my signalling to work even with heaps of help from Ray, I decided to go "back to the basics” using relays, switches, diodes etc that worked previously, albeit much simpler. 

Below is the Servo Installation etc at Werris Creek. 
The bottom of the Signal in the photo clearly shows the how Ray designed the operating "mechanism" with the 2 Adjusting Screws for the Signal Arm mechanical Stops. The Circuit Board in the photo is the Werris Creek NCE EB1 Circuit Breaker.

The small Bridge Rectifier (circular black item next to the L/H Servo), in the photo is my form of obtaining 12.0 Volts DC from the DCC Bus, to illuminate the Semaphores's LED. I have used this method of providing D.C instead of using a D.C. Power Pack to other accessories that need D.C. eg the Turntable at Murrurundi etc. NOTE: This method of obtaining D.C. from the DCC Track Bus CANNOT be done "inside" the Occupancy Blocks described below, as the block will ALWAYS show "occupied" due to the LED's current. Take the DCC from some other "NON" Occupied block of the layout.

Below is the Servo Installation at South Pangela, using a piece of 2 x 1 pine as shown and securing the Servo with one of the supplied screws. Simple easy installation, only time will tell if it's simplicity will last but for now it works.

Below is the the Signalling "Control Room", under North Pangela including the simple Servo Mounts (Marcus style), the Octopus III, 2 x NCE BD20s/Relay, a Relay and 2 Diode Matrix. While it looks like a bit of a mess, making it prettier by installing it onto some sort of Circuit board, was not warranted. Hopefully down the track I still be able to work out what's going on if something plays up.

Configuring the Octopus III.
My Semaphores will "mimic" the position of the appropriate Points that are operated by Toggle Switches using a Capacitor Discharge system, more details below. Operate the Toggle Switch for the Points to set the route through the Main line, a second pole of the Toggle Switch will operate the Semaphore to Green/Clear for the Main and Red/Stop, for the Loop and visa versa. Done by configuring the Octopus III to use:
  1. "Toggle" instead of "Momentary" Switches AND 
  2. Use the “Swap” feature where you can swap over the Servo “End Points”. 
This provided the correct INPUT condition to the Octopus III necessary to make the Occupancy Detection work correctly, that is a:

GREEN Signal, the Input needed to be OPEN.
RED Signal, the Input needed to a CLOSED (Ground). 

With Occupancy detected by the BD20s, ALL the appropriate Octopus III Inputs are "grounded" via the Diode Matrix, resulting in the Semaphores that are set at Green, going to RED and the Semaphores set at Red, not moving as they're already "grounded". The Diode Matrix looks after all the combinations. 

A little time swapping “things” around on the “spaghetti jungle” test version on the work bench and it work as I wanted. Eureka!! 

Configuring the Octopus and adjusting the settings for the Servo "End Stops" etc, is made easy by using the optional Remote Alignment Tool that comes with a 2.0 metre harness with RJ Plugs.

Simple hey!!!!

While this is not how the "real thing" works, it provided the automatic signalling I wanted, that is the Operators are "told" via the Signals when they can or cannot proceed from the appropriate location. Power is not removed from the track and yes Operators can disregard the Signal (and they do) but they may have a "head on" with another Operator and most probably banished to make the coffee.

When I install Semaphores into other than these "occupancy" sections, I'll figure out another method, maybe JMRI's Panel Pro etc but for now I'll go with mimicking the position of the relevant Point. 

My Occupancy Detector – a modified NCE BD20.
I have not installed resistor wheel sets to my Rolling Stock yet, so I can only “sense” the current drawn by a loco. Yes the train may still be “in” the block while the loco is not. Slight irregularity here but Operators can see the train when they enter the Yard/Loop, so it’s not an issue and it saves on adding resistor to wheel sets.

Due to the configuration of how I use the BD20, I connect 12.0 Volts D.C. (from local power) to Pins 1 and 4 and connect a Relay to Pins 1 and 3. With "occupancy" detected by the BD20, the Relay is energized and a GRD is supplied to the the Diode Martix, supplying a GRD to all the appropriate Inputs of the Octopus III, setting all the appropriate Semaphores to RED but this is okay with clean track/wheels.

Most of my locos have Stay Alive (see my Alive web page) so when power is interrupted to the decoder from dirty track/wheels, Dead Frogs etc, the Stay Alive powers the loco (and sound), through this power interruption. With the Occupancy Blocks being up to 15 metres long there could be some power interruptions that would cause the Semaphores to "cycle" from Red to Green to Red when the loco experiences a loss of power. To eliminate this "cycling" I have added a 2 second "delay" in de-energizing (NOT occupied) the BD20, by adding a 47 uF 16 V Electrolytic across Pins 1 and 2.

The Tam Valley Octopus III.  
Power: from the same “local” 12.0 Volts 1.5 Amps D.C. Supply (Power Pack) as above.
Inputs:  The wiring from the Points Fascia Switches etc have to be as short as possible (less than 2 feet) otherwise electrical “noise” may interfere with the operation of the Points and Signals. For the wiring to Werris Creek 5 metres away, the Fascia Switch operates a Relay under Pangela - now the input wire is less than 2 feet long.
Outputs: The wiring to the Servos can be much longer. I have spliced extra wire (telco 4 conductor) for the Signals at Murrurundi and Werris Creek where the wiring is up to 7 metres long and the Servos work fine.

My layout is of a walk around design, where you follow your train so you can "digitally" change your Points with your Index Finger and this method has survived for over 20 years but I intended to motorize the Points on layout where the "position" of the Points is hard to see and to those Points that are difficult to reach like Werris Creek, Port Waratah etc. With the installation of the Semaphores at Pangela the Points needed to motorized to "tie in" Semaphores with the Points. I needed to make my first Panel.

I had accumulated many Peco Point Motors over the years, so that's what I'm mostly going to use. These need some form of Capacitor Discharge system to operate AND I wanted to use Toggle Switches instead of "push/momentary" Buttons. The Toggle indicates which way the Points are thrown, hopefully eliminating the need to fit LED "indicators". My Occupancy system also required Toggle Switches (see above). NOTE All my Peco Electofrog Points have "Dead Frogs" also another "job" eliminated but I have Stay Alives in my locos to help here. 

Capacitor Discharge System.
Years ago I saw a Simple Capacitor Discharge Circuit from December 1994 AMRM by Gary Snow that uses a Toggle Switch, 2 Diodes and a 2,200/4,700 uF 25 Volt Electrolytic Capacitor (circuit copied below). Refer the original article for more details. 
I fitted the 2 Diodes to the Peco Point Motor and installed the Capacitor in the lead from the Negative of the Power Supply. You can use a smaller value Capacitors, in my case 2,200 uF 25 V instead of larger (3,300/4,700 uF) if you increase the voltage of the D.C. supply. making sure you don't exceed the Capacitors Operating Voltage. I made up a 20.0 Volt D.C. Supply from parts.  The value of the capacitance may need to be changed to get the Peco Point Motor to work - experiment here.  

Fitting more Semaphores
I have 6 Semaphores and 2 Bracket Semaphores to build. I'll fit the 4 Semaphores to Ardglen and the the 2 Bracket Semaphores to both ends of Murrurundi and using them as Starting Signals on the Yard and Loop and the single Semaphores on the what I call the "Main" with Murrurundi Station Platform. I'll replace the existing Colour Lights for the Broadmeadow to Murrurundi Occupancy Detectection section (block), all in the next few months now that I got essentially what I set out to achieve. 

I hope this Blog Entry gets you started in using these great Semaphores from Ray and Shapeways. Any question please don't hesitate to contact me.

This was one of the most rewarding modelling projects I have done on the layout due to fact that after making a start on assembling the Semaphore Signals, they were installed and working on the layout exactly how I wanted them to, all in about 3 weeks. To top it off, operating lighted Semaphores look fantastic.

For an overall operation of this section of the Main North, click on the video below. 

Operating Pangela with a few Operators.
A recent Operating Session after the above set-up was completed, an Operator had just completed a "rear end" bank to Ardglen and was returning the Banker back down to Murrurundi, stopping in the Pangela Loop, two trains from opposite directions arrived at Pangela jamming up Pangela with now where to go. Both trains had left Werris Creek and Murrurundi with a Green Starting Semaphore. This was not how the the signalling was supposed to work. 

Looking at how the prototype handles this scenario, they have a Signal Box with an Operator positioning the Lower Quadrant Semaphores with Levers, they use Timetables and Staffs/Bank Keys, where 3 trains/locos could never be at Pangela at the one time

The fix for me: 
1. Delegate a Visitor that's not running trains, to "operate" the Pangela "Box" just like the real thing. This will sort out these non observing Drivers or will it.
2. I want automated operation so I needed to have occupancy detection "inside" Pangela for both the Main and Loop lines. 

I've fixed the above Occupancy issue for Pangela by installing a third BD20. Once a Loco is detected (occupancy) for either the Main or Loop tracks, BOTH Werris Creek UP Starting Semaphores and the Murrurundi DOWN Starting Semaphores show RED while the appropriate Starting Semaphores in Pangela stay at Green. 

Having Semaphores on the layout with their Arms moving, is fantastic, thanks to Ray for his Semaphores and the flexibility of the Octopus III.

I've purchased further Semaphores to install Distant, Home and Starting Semaphores between Broadmeadow and Tamworth including Ardglen where I'll increase the length of the Loop. 

The latest Semaphore additions - 8Mar17.
I've installed 3 Semaphores "inside" Murrurundi, shown below with the Northern Tablelands Express departing, instead of the single Semaphore "outside" as described above and in the video.  A Triple Bracket UP Home Semaphore will be added to the left of the photo.

Controlling the Semaphores and of course the Points, required another Control Panel.
Experimenting with different methods of displaying the track on the Panel, I chose painting the 300 x 100 mm Aluminium Sheet after drilling the appropriate holes for 29 3.0 mm LEDs and 9 Switches (6 x DPDT and 3 x 4PDT), with Yellow paint, applying 3.0 mm Tape for the tracks then painting with flat Black. Drill out the North Murrurundi fascia for access and clearance and attached using a 100 mm long hinge. Making this and other Control Panels will be my next Blog topic.

The illuminated LEDs show the route through North Murrurundi, making selecting the correct "road" for Visitors, easier.


  1. Wow Marcus, you move quick. You were only talking about implementing this system a few weeks ago. Well done.


  2. Marcus
    Thanks for the plug, my Signals Branch Shapeways shop can be found at:

    I added this information here as searching Ray Pilgrim on Shapeways won't find my shop.

    Ray P

  3. Marcus,
    I agree with Bob, very impressive. It certainly enhances the feel of operating in the 1960s.
    cheers Phil

  4. This comment has been removed by the author.

  5. Bob, Ray and Phil. Thanks for your comments. Bob, finishing a project a month after starting it was very satisfying. Ray, I've added your Shop url. Regards Marcus

  6. Marcus,
    Great work but more importantly thanks for sharing you work with us, Regards,
    Phil Collins

  7. Marcus, starting the process on Wattle Flat and enjoyed your post. Thanks for the information, greatly appreciated. Darren

  8. Hi Darren. As you'll see adding Semaphores adds one more dimension to the scene. Discussing with friends on Friday night on how to "operate" a Block with Semaphores using a Staff etc or using Levers in a Signal Box etc. These are "manual" methods but I need an automatic form hence my "Occupancy Detection" and the Diode Matrix. I'm looking forward to seeing how the Staff method works but for now and my future Semaphore installations, I'll use my automatic method. Let us know how you "control" your Semaphores.