Basic Block Wiring Assistance

I am not as familiar with fast track, but why not use insulating pings in the middle rail (same with the outer rails if you are using the outer rails as a detection circuit. You could cut a gap, but why bother if you can use pins. Another option some people do is use a dab of silicone caulk in the gap to keep it apart.

Note with the fast track to use it as a detection circuit you will need to make sure that the outer rails are insulated from each other, I believe on fast track you can remove a clip on the bottom of the track section that bridges the 2 out rails.

And yes, you could create sub blocks for signals only, would mean that the outer rail would need to be isolated on one side by a gap of pin. So if you power block is 10' long, and you want 2 5' sub blocks, in the middle of the section you would cut a gap in the appropriate outer rail, and the signals would be wired to their sub block. For power, the middle rail would be continuous and one of the outer rails would be the common return to the transformer (the non isolated rail. The signal ground would come from the isolate rail side.

@bigkid posted:

I am not as familiar with fast track, but why not use insulating pings in the middle rail

There are 2 middle rail pins at each juncture, set into molded holes in the roadbed of each piece. This requires partial disassembly of the track to remove them. Replacing with insulating pins accomplishes nothing... just leave the gap.

>make sure that the outer rails are insulated from each other
Yes, I will eliminate the under-track jumpers to isolate the side rail.

>just leave the gap
Can I do it with both the center and common side rail or is that asking for trouble?

If you are talking the sub block, you wouldn't need a gap in the center rail for any reason I could think.of. so for let's say a 10 foot block,you would have a gap in the center rail at either end. Then you would have a gap on one side common rail at the start, at 5’ ( delimiting the first sub block for signal), then a gap at 10' to finish the second signal sub block

And I apologize w fast track and insulating the middle rail, I forget that they have tabs on the roadbed that maintain continuity between sections. 

To answer your initial question:

Yes, you can create a "subordinate" insulated section (or several) within a larger section very easily.

There are a few steps to doing this. The short answer is "DC and a diode"

You need to create (or purchase or acquire) a DC supply of about 12 to 16 volts. It is recommended that you use a supply that is robust enough (has enough amperage rating) to handle additional loads as your empire gets bigger.  DC is the preferred type of electricity for signaling, due to the fact that relays can be made to slow release, circuits can be made to eliminate chattering, and diodes can be used for logic.  Diodes can be considered "electrical check valves" but only work on DC.

You will connect the negative side of this DC output to the AC wire that supplies outside rail power. Now, the AC traction "return" and the signaling "return" are tied together in common.  No phasing is necessary.

Create the larger insulated section by isolating the outside rail, using whatever method you choose. Air is my choice, but a wooden matchstick or a plastic pin will work. Within that section, make two more cuts in the insulated rail.

Fasten (solder) a wire to each of these three sections.

The wires from the 2 outer parts (#1 and #3) get connected together and then connected to one of the terminals of the signal circuit.  (more later on what kind of signal you will be using *) The wire #2 from the subordinate section goes to one terminal of the crossing gate.

Both the signal's and the crossing gate's "other" terminal get connected to the positive side of the DC supply.

At this point, whenever a train is present, negative DC flows from the two outer track sections to the signal circuit and then through the signal to the positive side of the DC supply.   When a train is present on the subordinate section, negative will flow to the crossing gate, through the gate, and then to the positive DC supply

The only thing now to solve is "Whoa, Shorty, what about the fact that the signal will lose power when the train crosses the gate section?" Aha! Good question, Slim.

Connect a diode between the gate wire and the two signal wires, with the arrow pointing towards the gate wire. This allows negative DC to activate the signal but conversely, blocks the negative from the signal wires from activating the gate.

ins section     sub section     ins section

wire 1                wire  2             wire 3

signal -> pos       gate->pos     signal -> pos

diode

left side towards signal wires (1 and 3)  right side (arrow) towards gate wire (#2)

Sorry, I don't have circuit-drawing capability on this computer. Maybe someone else will step up and draw the circuit more accurately.

*If your signal is a two-lamp (red/green) type, like a 153, the signal wires need to activate a relay that switches power from the normally green indication to the red indication when there is a train present. (Or maybe you intend to use a later model that only requires a single wire activation.)  If you are using a semaphore (like a 151) you don't need the relay.

Ah yes, makes perfect sense the diode was what I was missing. I knew I needed something to keep the flow from the signals into the gate. Thanks!

You're pretty Sharpe, Stephen.

If anyone wants to do this circuit but doesn't want to use DC, relay logic can replace diode logic.  AC relays will work.  Diodes are cheaper (10 cents) vs relays (a few bucks.)

I've decided to go with AC relays, specifically with the JWA Insulated Track Signal Driver. I will have one JWA board on the block's primary insulated rail (that operates a block signal) and another board on the sub-block (that operates a crossing gate). As discussed I would like to pass the sub-block signal to the main block signal, but not have the main block signal go into the sub-block signal. Would I still use a diode or is there an AC equivalent to create a one-way gate?

Since my signals and the MTH crossing gates I'm using are DC. I could put the diode between the Yellow (gate down position) of the MTH gate to the Red (occupied) light on my block signal. That way when the gate is triggered the signal will stay red.

Does this look correct?

Since the red and green LEDs are independent, my gut says there are conditions where both red and green are lit when adding the diode.

Ah yes, no train in block 1A makes the signal green, but a caboose stopped in the crossing (block 1B) turns on the red light too.  Ughh...

I think you need to try the diode in the sense line between the 2 blocks. You would be creating an OR- one or the other both can trigger the block signal, only the block to the gate crossing turns on the gate crossing. I'm just unsure of diode polarity of the sensing circuit.

Again, just unsure of the diode polarity and I think it works but obviously you have to test. I don't have 2 of the boards to test with.

Ah! Thanks...  in my google research I misunderstood that with AC half the voltage would go through. (So I thought somewhere between 0-9 volts would leak through.) But reading more I see:

• That diode in the primary valve’s circuit is actually blocking half of the current. That’s how diodes work in AC. A single diode won’t block all the current like it can in a DC circuit, but it will always block half of the AC current, no matter which way the diode is oriented. The only difference orientation makes is whether the diode blocks the positive or negative side of the sine wave.

So I just need to determine the correct polarity of the diode to block the correct side of the sine wave.

Should I use something like this?

Well, I failed and that's OK, better to know now.

A diode in that position between the 2 sense leads won't work as you intend to make an "OR" gate.

I just tried the JWA track sensor (granted I only have one) but the point is, you put a diode in series in the sense lead, and EDIT: in my original theory, one direction the diode would block sensing and the other direction the diode would allow sensing. However, testing, the sensor still detects a short to common regardless of diode direction. So basically no, a simple diode in the sense line would not "OR" the one block, it "OR"s both directions meaning you might as well just have one block.

Edit:

Again, my theory seeing a 3 pin regulator on the board and not reverse engineering it, I incorrectly assumed the sensing circuit might have been DC for the relay coil. In other words, the sense wire would have been a low voltage DC potential and that would allow the use of a diode in series to block the sensing or combine the sensing from multiple isolated blocks. That's not the case, I think the bridge rectifier allows for AC or either polarity DC sensing- a good thing, it just defeats my quick and easy hack of adding a diode to your specific circuit.

OK, so reviewing this circuit, there are dozens of ways to skin the cat. The problem is, all of them are complicated or more parts.

Example, what IMO would be ideal, is replace the relay on the gate arms JWA board with a DPDT relay and then use that second isolated set of contacts driven, to trigger the other block signal board just in parallel to the track sensing block.

Another option that is higher cost, is add a third JWA board.

The 3rd board is was ensures that the block signal is triggered when only the road crossing block is activated.

Thanks for helping me think this through! I see the point of the relay or third board is to control which board operates the block lights/signals. Looks like there is no easy way to piggyback the Gate Sence signal into the Block Sense signal. Sounds like a diode isn't the solution. Back to the drawing board.

How about this? Put a 12VDC relay in-line on the GREEN block signal lamp. Its normally closed allowing the Block Sensor to control the Block Lamps. When the MTH gate goes down the circuit to the Red lamp is shorted AND the relay is activated opening the Green block signal lamp. Also, I believe it will allow me to use signals from multiple (sub-block) crossings in this block. Thoughts?

A very respectful suggestion, before you invest a bunch of money, time and effort into Fastrak, you might want to get Gargraves, Ross, etc.  Trackwork is much easier to divide into blocks.  I have 73.  Also, Ross turnouts are much better quality.  Fastrak was designed to be used for temporary quick set up.  Not writing this as a "put-down."  Just a very respectfully suggestion.

Fastrack much more challenging to "divide" into blocks and has issues with contacts on the ends of sections.

John C. that's good advice. My layout is a small 5x9 ping pong table and the Fastrack has already been laid down and divided into blocks. So for this project, I'm tied to Fastrack. But I agree... the time and effort I invested to isolate the outer rails, solder jumper wires, and remove the various pins to create the blocks between the ~100 individual pieces of Fastrack was a lot of time and effort. If (when?) I build a bigger permanent layout Gargraves or Ross will likely be my choice, (plus I hear it is quite a bit quieter). This is my first layout and appreciate the input I'm learning a lot along the way from everyone here on the forum!

These may be of some help: Ultrasonic Train Detector Kits

Here we go again... my last drawing assumed the blue wire feeding the gates went to DC ground but that is not the case. It completes a circuit inside the gate.

This drawing uses the JWA detectors to close a DC ground circuit controlling 2 relays each. Relays 1&2 pass the Block Detector signals to the red and green lamps. Relay 3&4 short the connection between the gate blue and the white/yellow.

When the Gate Detector Yellow circuit is closed, Relays 1&2 open, the Block detector is disconnected from the lamps, and the red lamp circuit is shorted. The diode keeps the Red lamp signal from the Block detector from shorting the gate-down circuit.

What do you think?

Stephen I would just be wary of overdoing it.  One of the great strenghts of traditional 3-rail O gauge is the robustness and redundancy afforded by having two ground rails.  Many of today's locomotives have rubber tires, and/or they rely on the ground side of the circuit for command control information.  Having too many gaps risks a loss of signal, or a loss of continuity.  I would test your arrangement on the floor to make sure it works reliably before you build it into a permanent layout.  Personally I would consider some type of trackside detector (infrared, etc.)  My $.02.

I'm using Arthurs suggestion of 'DC and a diode' to pass control of the Block detection to the Gate sub-block and then back to the Block detection after the Gate sub-block has cleared.

To do this I made up a relay board to connect to the two JWA detectors. The first JWA is connected to the isolated rail in front of and behind the Gate sub-block. The second JWA is connected to the Gate sub-block.

1. The JWA1 Block Detector when ON passes its NC signal through relay R2 to power the Red lamp
   The JWA1 Block Detector when OFF passes its NO signal through relay R1 to power the Green lamp
   
   
2. The JWA2 Gate Detector when ON
   A) Turns ON the red and green lamp relays R1&R2 to disconnect the powerr to the Red & Green Lamps
   B) Shorts ON the Red lamp (through the diode)
   C) Turns ON relay R3 connecting the yellow and blue gate wires to put the gate down.
   The JWA2 Gate Detector when OFF
   A) Turns OFF the red and green lamp relays R1&R2 (allowing the JWA1 Block detector to operate the Block signals again)
   B) Disconnects the short of the Red lamp
   C) Turns ON Relay R4 connecting the white and blue gate wires to put the gate up.

This allows me to operate the Block signal Lamps and MTH Gate with DC, to pass the Block Detection to the sub-Block and back. This will also allow me to have multiple sub-blocks in a single block (I have one block on my layout that has three roads crossing the block and I have one Gate that has three blocks passing through the Gate). In the future, I can also use the DC to turn on crossing bells or I can even connect an Optocoupler (to the Red Lamp out) to tell an Arduino where there are trains on the layout.

Next up is to wire these relay boards, block lamps, and crossing gates into my layout.