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digitrax signaling/ detection

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  • Member since
    March 2009
  • From: Harford County, Maryland
  • 86 posts
digitrax signaling/ detection
Posted by mmr1229 on Friday, October 2, 2009 3:26 PM

im looking for some direction on signaling for my digitrax system, basicly for prototypical purposes only (looks). i dont know where signals go, how they are used or how to insall them, i also would like the booster to be able to automaticly operate the grade crossing signals. i am almost positive that you can do this with the ds64 stationary decoder, however i dont know how to wire it. basicly i am 100% lost when it comes to railroad signaling and i need all the help i can get.

  • Member since
    May 2002
  • From: Massachusetts
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Posted by Paul3 on Saturday, October 3, 2009 11:39 AM

If you just want signalling to be cosmetic, you don't need anything other than some signals and some DC power supplies.  They won't change color, but they will be present and lit up.

If you want the signalling to operate manually, you can buy a Digitrax SE8c, which is basically a large stationary decoder for signalling.  Each signal head will have two switch-like addresses that can be changed from "Throw" and "Clear" using the Digitrax DT-series throttle.  This means that every signal can have 4 aspects.  These can be red, yellow, green, and a flashing color (like flashing yellow).  Of course, you can also wire up rotary switches on the fascia and get the same results without an SE8c...other than the flashing aspect.  That would require a bit more work, but even that could still be done without an SE8c.  These will still not be automatic and will not change color as the train goes around the RR, but it's better than just being green, yellow, or red all the time.

If you want the signalling to operate automatically (and realistically), then you need detection and a computer.  The detection tells the devices where the trains are, and the computer supplies the logic that you provide using a program like JMRI or Railroad&Co.'s program suite.

Digitrax detection is provided by BDL168's.  You need to wire these into the railroad in series.  A single BDL168 does 16 blocks worth of detection.  You route the power from your DCC booster or brain straight into the BDL's inputs.  Then you have the 16 outputs from the BDL that you must route to your track blocks.  Every time power is drawn from the track, it passes through the BDL and activates the detection for that block.  This information is broadcast into Digitrax' LocoNet and can be used to light up LED's on a fascia via isolated outputs on the BDL itself.

Now that you have BDL168 detection and you have SE8c's to operate the signals, you must have a PC and load the free JMRI software or the pay Railroad&Co. software to provide the logic.  The PC must also have a LocoNet connection, probably using the Digitrax PR-3 (tho' others are available from 3rd parties).  The PC will see the detection signals broadcast from every BDL168, but it won't know what to do about it.  That's when you have to provide the logic for the signalling.  This needs to be programmed into the software using If-Then statements, like, "IF Block 2-15 is occupied, THEN Signal 653 shows Red AND 652 shows yellow."  This is all done with pulldown menus, so it's easier than it looks.

So, for working signalling using Digitrax brand items, you need at least one of the following:
BDL168
SE8c
PR-3
Computer
JMRI or RR&Co. software

Working signalling is the most complicated thing one can do in model railroading, IMHO.  You can see why...  Smile  I mean, DCC is a snap compared to signalling.

Paul A. Cutler III
*******************
Weather Or No Go New Haven
*******************

  • Member since
    May 2002
  • From: Massachusetts
  • 2,899 posts
Posted by Paul3 on Saturday, October 3, 2009 12:01 PM

Oh, and I should have answered your other questions.  Blush

Signals should be placed at all interlockings at the very least.  IOW, at all crossovers, where other lines branch off, yard entrances, etc.  These signals should have 2 or 3 heads on them. 

Mainline signals should be placed every so often around the layout to cover both directions of travel.  They should be spaced further apart then any train length you would normally operate.  The signals adjacent to interlocking signals should be of the "Approach" type (two heads, one offset to the right or with a yellow semaphore blade).  The other mainline signals can be a single head (depending on the prototype).

To install them, drill a hole and stick them in.  Smile  You can build a little base for them out of wood, plastic, or plaster.  Walthers Goo or silicon is probably the best way to secure them.  It has a little give to it and can be cut away to allow for replacement or maintenance.

Grade crossing signals can be operated with a DS64.  However, it only has two wires for such things, so it alternates DC current to light up the LED's in the crossing lights.  This means you must have a crossing light wired so that it works like that, but many do not.  Some use the same common wire for all the LED cathode leads (or anode), which means the DS64 will only cause all the lights to flash all at once.  What you need is a crossing light that has half the LED's common wired to the anode, and the other half to the cathode...then the D64 works fine.  The older DS54 (out of production) didn't have this problem as it used four wires for outputs, but then it was $20 more.

In any event, one can use the DS64 to operated grade crossing lights automatically by wiring the LED outputs of a BDL168 to the inputs of the DS64.  See the manual at Digitrax.com.  IOW, when the BDL is occupied, instead of lighting up an LED, it will activate the DS64.

BTW, Model Railroad News magazine has been running a multipart series about DCC signalling the last several months.

Paul A. Cutler III
*******************
Weather Or No Go New Haven
*******************

  • Member since
    January 2007
  • From: Eastern Shore Virginia
  • 3,290 posts
Posted by gandydancer19 on Saturday, October 3, 2009 5:30 PM

 Start here.

http://tinyurl.com/mrr-signals  (copy & paste in your browser)

Hope this helps.

 

Elmer.

The above is my opinion, from an active and experienced Model Railroader in N scale and HO since 1961.

(Modeling Freelance, Eastern US, HO scale, in 1962, with NCE DCC for locomotive control and a stand alone LocoNet for block detection and signals.) http://waynes-trains.com/ at home, and N scale at the Club.

  • Member since
    June 2003
  • From: Ponte Vedra, FL USA
  • 129 posts
Posted by mrnimble on Tuesday, October 6, 2009 2:46 PM

Don't overlook signalling by CML Electronics (www.cmlelectronics.co.uk).  This system interfaces well with Digitrax as well as RR&Co. software.  Their SIGM20 system also has a programming utility that you can run on a PC that allows for you to configure your signalling system to fit your layout so it will operate automatically and prototypically on its own so no external software is needed.  It also comes with a fine manual and tutorial to help solve all of your signalling issues.  Best of luck.

  • Member since
    March 2009
  • From: Harford County, Maryland
  • 86 posts
Posted by mmr1229 on Tuesday, October 6, 2009 6:07 PM

thanks everyone, the information was very usefull. just need to learn how it is to be wired. i'll be a while.

  • Member since
    February 2002
  • From: Mpls/St.Paul
  • 13,892 posts
Posted by wjstix on Wednesday, October 7, 2009 2:51 PM

If you want a sort of in-between signalling system (working, but not fully prototypical) Circuitron and some other companies make systems where you can install either a wired-in track detection circuit or an electric eye type activator that will make a signal go from green to red when the block is occupied or the electric eye is covered. Some of them can be set so once the block / detector is clear, it will remain red for so many seconds, then show yellow for so many seconds, then back to green until activated again.

Stix

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