Links:
NMRA
 
The Signaling Solution, Inc.
PO Box 25
West Terre Haute,
IN 47885
 
Phone:(812) 533-1345
Fax:(708) 570-6140
 
Email:
retailsales@wsaeng.com
dealersales@wsaeng.com


FAQs
BD8

I've checked out your BD8, and the board itself is working fine. So, why does a block go 'occupied' and stay that way, even when the train leaves the block?                                                                                                - Dave

The DCC track voltage itself causes the problem. Pardon me if I get a bit technical here.

As you know, the DCC track voltage is not a DC (direct current) type of signal. In reality, it's a high frequency AC (alternating current) signal. Every time the voltage switches from positive to negative (about 10,000 times a second!), the wiring between the booster, BD8 and track has to change polarity. If the track wiring for a particular block is sufficiently long, the circuit can have enough AC current flowing to charge and discharge the wires, that the BD8 sees the current and detects it. Sometimes this 'stray' current can be large enough that the block always shows occupied; sometimes the stray current is just large enough to keep the block from returning to vacant after the train leaves.

I have a block like this on my test layout, and used it to help test your board after all the normal tests show the board was working fine.

It's hard to predict the length of wiring needed to cause this effect. I suspect that your block 5 probably has longer wires than any of the other blocks you've wired so far. If you've used twisted pair wiring for this block, I'd begin by suggesting that you run physically separate wires to the block from the booster and the BD8.

If you've already done this, we can install a capacitor on the BD8 connector that should solve the problem. I've put three of these capacitors in the package with your board. Simply connect the capacitor from any of the layout common pins 5, 6, E or F and the common rail input pin for the problem block. In this case, this would be pin B. Make sure the capacitor leads don't short to each other or any of the other wires on the connector. Unless the block wires are incredibly long, this should fix the problem. The extra capacitors can be used if any of your other blocks have a similar problem. These capacitors are not polarized, so it won't matter which lead is connected to which pin.

You're probably wondering why these capacitors are not on the BD8 when we build it. Actually, there are capacitors already on the board. Like most engineering situations, there is a compromise involved. The larger the capacitor value, the greater the current needed for the BD8 to detect the train. While a motor or bulb will always be detected, I've tried to design the board to be able to detect a single car with a detectable axle. So the BD8 is shipped with capacitors small enough to allow this to happen. For most layouts, this choice seems to work fine. Adding one of these additional capacitors will reduce the sensitivity of a detector to the point where a single car is still detectable, but just. You'll still have no problem detecting engines and cars with bulbs.

 
Detectable Wheel Set

I came across your website while looking for detectable wheel sets for my N scale layout. I’m currently in the process of changing over to DCC. I’d like to get some information about the N 33” wheel set. I’d like to know the resistance of each wheel set, how many of these wheel sets can be on a 5 amp power district at one time, whether they can be placed in micro-trains trucks and what the wheel sets look like (how the resistor is attached). If you could send a photo of them, that would be great. I’d also like to know if you have volume discount. I would need approximately 600 wheel sets (around 300 cars). I wouldn’t be able to have all these cars on the layout at one time, but would like them to be ready when they’re placed on the layout.                                                                                                                                                                            -Roger Gollon

We use a 5.1 K resistor on each axle. That means that you should be able to have over 1600 axles in a 5 amp booster district. Since most people only use 1 axle per car, a district that big will be huge!

I don’t have a photo, but can describe it pretty well. We use a NWSL wheel set and install a resistor (0.08” x 0.05” x 0.03” thick) so that it bridges the insulation at the center of the insulated wheel. One end is against the back of the wheel, the other on the axle. It’s hard to see when you’re holding the wheel set in your hand, and virtually impossible to see when the axle in installed in a car. You can weather the axle and resistor using any of the standard techniques. The wheel treads need to be clean so the pick up power from the rails.

We sell the axles in packs of 4, so you’ll probably need 150 packs. We can offer a 10% discount on an order like that. Unfortunately, since this is a manual assembly process, we really can’t discount it any more than that.

As you know, there are different axle lengths for N-scale wheel sets. The length you need depends on the brand of trucks you’re using.

 
 
G'Day from Down Under. Our electrical supply is 240v. Have you configured any units for Australia? Thanks                                                                                                                                                                                 -Stuart Hall

Our products operate from an AC wall adapter that produces 9-12 VDC at 500-900 ma. The units we include with the products have US plugs. All of our other ‘down under’ customers have been getting their ‘wall warts’ there, and we discount the cost of the boards and leave out our adapters.

It seems to work well this way. Until our down under sales volume is high enough to justify stocking the right units, this seems to be the most cost-effective solution.

 
What would show for "medium clear" and "slow clear" as I don't know what the "shows" configurations would be.
- Steve

You need an aspect chart for the railroad and era you're going to model. The reprint of the John Armstrong "All About Signals" article will give you a representative chart from the era that article was written. I've attached a current BNSF chart. They do route signaling rather than speed signaling. And, the link http://raildata.railfan.net/java/DivRte/NORAC.htm is a great way to check out the NORAC aspects.

Speed signaling: the signal aspect (e.g., red over red over green gives the indication "slow clear") tells the engineer what speed is safe for the route ahead.

Route signaling: the signal aspect tells the engineer the route he is to take. He has to consult his rule book to find out what the appropriate speed is for the diverging route he is about to take.

The route itself would probably have been set up by a local towerman using a manual interlocking plant, or by a CTC dispatcher who could be located almost anywhere.

If you use Google to search the web for "railroad signal aspect" or something similar, with 'railroad' being the name of the specific railroad you're interested in, you'll get a lot of links. The link above was the first listed after I googled for "norac signal aspect".

Also, the "stop" aspect (red, or red over red, or red over red over red) can actually be displayed in several ways, depending on the signal head being used. For example, if the railroad uses upper quadrant semaphore signals, all 1, 2 or 3 arms would be horizontal. If they use position light signals (PRR), each head would have the three horizontal bulbs lit.

What the prototype does when installing signals is to make a list of all the aspects that need to be displayed at any given location. Then, they use the lowest cost head configuration that provides all of them. For example, if all they need are the aspects "clear", "approach" and "stop", a single head will be sufficient. Add more aspects to the list, and they'll have to add one or two heads to be able to display them all.

Within the US, both types of signaling are in use. If you want to model a specific railroad and era, you have to get that information either from them (if they're still around) or from their historical society if they're not. You can quite often find a copy of expired rule books and time tables at local train shows. I've bought a few myself over the years.

The Phillips book from Simmons-Boardman "Railroad Operation and Railway Signaling" has a good chart that shows the AAR aspects in use in the 1950's and earlier.

 

Thank you for taking time o talk with me today about some resources to read to help my understanding of signaling. If you do come across that web site, I would appreciate a heads-up form you as to its url. I noticed a rather long string of discussion on a yahoo site regarding signaling for double slips. Does your equipment handle such situations?

- Steve

Here is a web site with a lot of really good information: http://www.lundsten.dk/us_signaling/

You can think of a double slip as a pair of regular turnouts joined at their points. In other words, two routes in on one side, through a short piece of track, to two routes out the other. Assuming that this is the only piece of track in the interlocking plant, you would have a two or three head signal on each of the four routes into the plant. The choice would depend on which prototype you're following. For any of the straight through routes with all blocks ahead clear, the entry signal would show "clear"; for any of the diverging routes, the entry signal would show either "medium clear" or "slow clear", depending on the rated speed of the switch. Since double slips tended to be rather short (#6 or so), the diverging routes would typically show "slow clear" as their least restrictive aspect.

 

I have a question regarding the BD8 Block occupancy Detector. I have wired up the board and terminal strips in an enclosure, successfully tested the board locally and I am now in the process of doing the final connections to the tracks and signals. However, My layout is powered with the Digitrax DCC system and includes the Loy's Toys Automatic reversing circuit http://www.loystoys.com/loystoys/arsc.html for two reverse loops. My question is as follows. As I would also like to protect the reverse loop track with signals, can the BD8 function within the reversing sections while at the same time operate on the rest of the layout even as the polarity (Common) changes automatically in the reversing sections as a train enters the loop depending on the direction of travel? If so, how can this be accomplished in simple terms? Thank you

The BD8 can do this.

What you need is a DPDT contact set. I’ve attached a simple drawing that shows how. The contacts can be thrown by the turnout that enters the reverse loop or any other means. I’ve shown the BD8 connected in the booster “Rail-B” output, but it can be the other way around. The “DET” line is the detector connection to the reverse loop. It can be any of the 8 in the BD8. Just wire up one of these circuits for each of your reverse loops. I haven’t used Loy’s circuit, but I have tried others. So far, they all draw track current and the reversing circuits themselves are detected by the BD board, with or without a train present.

 

Please give some details on using my BD16 to run signals with block detection on my Digitrax layout, thank you.

- Winston

Our BD16 detects your trains in up to 16 separate blocks. The manuals for all our products are on our website (www.wsaeng.com/Signaling_Solution) and can be downloaded for free. For simple Red-Green signals, our BD8 and BD16 boards have corresponding “occupied” and “vacant” that will operate your signals directly. If you want 3-aspect signaling, you would add one or more of our MSC Master Signal Controller boards. The MSC has 18 built-in typical track configurations that you can select with push-on jumpers. Then, connect it to the BD16 outputs and signals as shown for that configuration and that’s it!

Typical wiring diagrams for all this are included in the various manuals.

 
I am still confused about how the MSC cards in mode 4 & 15 are wired (to the block occupied & signals) to achieve what you originally intended when the system was sold to Vic.

On the drawing supplied by Vic and sent back with the information by yourself, it was noted that for this 3 way junction the following would apply:- MSC-3, Mode 10

1/4 MSC-9, Mode 4
1/3 MSC-8, Mode 15

The mode 10 is fully understood it is only the other two that are confusing me.

Please let me know your thoughts.

Are you suffering a cold winter where you are? We are suffering from a very cool summer at the bottom of Australia? The tennis is on here at the time being and we ahve had awful rain storms. My oldest son has just returned from 3 weeks in California (LA & San Diego) and it was very pleasant weather whilst he was there. In fact it was actually warmer over there than here.
How did your signalling system come about? What is your normal daytime living?

-Noel

Mode 4 is used to operate four separate 3 aspect heads. One way to use mode 4 is this: assume you are signaling a sequence of 5 blocks in a row for a single direction of traffic. You would use mode 0 to control four of the signals, and ¼ of a mode 4 MSC to control the 5th. 

Mode 4 can also be used when the track diagram does not match any of the predefined track diagrams for the other modes. Think of each of the four elements as a “signal head controller” that provides the logic needed to select and generate the proper aspect based on the two blocks that follow the signal and the block ahead if approach lighting is used. The basic aspect logic says “display red if the home block (block right after the signal) is occupied, display yellow if only the advance block (block immediately following the home block) is occupied, and otherwise display green.” If approach lighting is active, the head is turned off if the approach block (precedes the signal) is vacant. The head control logic has more to do if the signal uses a searchlight head. In this case, it has to blink the red and green colors of the 2-color LED to generate the yellow aspect.

When you have a track diagram that does not match any of the predefined diagrams for the other modes, mode 15 is used. Think of each block as some switching logic (a group of SPDT contacts) that operates along with an associated turnout. Just as the turnout routes trains from one of the three tracks to one of the others, based on turnout position, the logic block in mode 15 routes the “occupied” output of block detectors in the same manner. The occupied output of the block at the points is routed to the signaling circuitry at the selected frog block, and an occupied (ground) is routed to the unselected frog block. Similarly, the occupied output from the selected frog block is routed to the signaling circuitry that controls movements toward the points.

Example: for the block tied to the points of a turnout, the “next” block depends on the position of the turnout. So, if I need to know whether the “next” block is occupied or vacant, I can route the occupied output from the two block detectors through a mode 15 box. For a block tied to the frog, the “next” block is forced to appear occupied if the turnout is thrown against the route to that block. If the turnout is thrown for the block, the occupied status of the point-side block is passed through.

Look at the upper left mode 15 box. The turnout is associated with is right below the box. In general, arrows pointing toward the box represent wires from block occupancy detectors, and arrows pointing out represent wires carrying block status to a signal head controller, such as a mode 4 box. The arrow pointing up at the bottom of the box represents a wire connected to contacts on the turnout motor.

Mode 15 boxes can be connected together just as the turnouts are connected together so that occupied outputs of various block detectors are routed through just as the trains are routed through.

My suggestion for handling your 3-way assumed that you would be using speed signaling and both diverging routes would be medium speed. For this, the entry signal (mode 10, 1E) only needs 2 heads.Since this is my first truly “detailed” look at your 3-way logic, it may differ a bit from my earlier suggestions.We’ll use ½ of a mode 4 MSC to control the 2 entry signals from your 2 diverging routes; we’ll use the mode 10 MSC to control the two headed signal entering your junction, and the main route signal entering from the frog side.We can ‘trick’ the mode 10 logic as follows. Look at the mode 10 figure. We’ll want the mode 10 MSC to control 1E the same no matter which diverging route you’re using (both diverging routes assumed to be medium speed). So, the mode 10 T-2 contact has to be pulled to ground when either of your switches is set for diverging. You can use SPDT contacts on the two Tortoise motors to do this. The diagram below shows how this is done. The diode can be almost any low current switching diode such as a 1N914 or equivalent.Use all three MSC Mode 15 boxes to handle the occupied routing. One will select the occupied output of either block 13 or block 8 as the BD-2 input (pin C) on MSC mode 10.

The second will select the occupied output of either the block beyond 567 (SW? = normal) or the block beyond 8 (SW? = reversed) as in input to the third Mode 15 box. The third Mode 15 box is controlled by SW3 and will select the occupied output of the block beyond 13 (SW3 = reversed) or whatever is selected by the second Mode 15 box. The selected output of the 3rd mode 15 box is connected to the BD-0 input (pin A) of the Mode 10 MSC. All of this will let the Mode 10 MSC control signal 1E properly.

The two Mode 4 boxes that control the entry to the junction from the diverging routes will have their distant block inputs connected to their pin V. This will force them to show “approach” (yellow) as their least restrictive aspect. We’ll use the mode 15 2nd and 3rd boxes to pass the occupied output of block 4 through to the home block inputs for the 2 mode 4 boxes. What this will do is force each of these heads to red if its diverging route is not open, or if block 4 is occupied. One of the heads will display yellow if its route is open and block 4 is vacant.

This may be a bit confusing for you, and for that I apologize. Please let me know if you need a little clarification.

 
I have a question regarding the BD8 Block occupancy Detector. I have wired up the board and terminal strips in an enclosure, successfully tested the board locally and I am now in the process of doing the final connections to the tracks and signals. However, My layout is powered with the Digitrax DCC system and includes the Loy's Toys Automatic reversing circuit http://www.loystoys.com/loystoys/arsc.html for two reverse loops. My question is as follows. As I would also like to protect the reverse loop track with signals, can the BD8 function within the reversing sections while at the same time operate on the rest of the layout even as the polarity (Common) changes automatically in the reversing sections as a train enters the loop depending on the direction of travel? If so, how can this be accomplished in simple terms? Thank you.

- Stephen

The BD8 can do this.

What you need is a DPDT contact set. I’ve attached a simple drawing that shows how. The contacts can be thrown by the turnout that enters the reverse loop or any other means. I’ve shown the BD8 connected in the booster “Rail-B” output, but it can be the other way around. The “DET” line is the detector connection to the reverse loop. It can be any of the 8 in the BD8.Just wire up one of these circuits for each of your reverse loops. I haven’t used Loy’s circuit, but I have tried others. So far, they all draw track current and the reversing circuits themselves are detected by the BD board, with or without a train present. I hope this helps.

 
 

The Signaling Solution, Inc. PO Box 25, West Terre Haute, IN 47885