Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Question for the DCC Gurus

1724 views
10 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Wednesday, April 27, 2016 9:08 PM

Thank you Randy, I’ll check them out.
 
 
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Wednesday, April 27, 2016 8:44 PM

 The Circuitron AR-1 (not to be confused with the Digitrax AR-1) may be what you need. It uses IR sensors to flip a relay, by putting them at the proper points of the reverse section, it cna change the polairty of the main automatically as the train passes, replacing your DPDT toggle.

 Dallee also has the TRAK-DTRL which effectively does the same thing but with current detection.

 Both manufacturer's web sites have wiring diagrams for their respective products.

                                        --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Wednesday, April 27, 2016 6:24 PM

richg1998

 

 

You would have to use a DPDT relay to do this with optical detection. To my knowledge, the only way to do this. I have seen this question in various train forums and the same answer and the response is, DPDT switch.

 

Rich

 

 

I guess the hard way is the only way this time Rich.  I was hoping for a magical box that didn’t need any brain power.
 
I have enough P&B KHA17 12 volt 4PDT 5 amp relays with sockets on hand to build a multi loop reversing system and I have enough room for everything inside my control panel.  I used EURO connectors for my block distribution so that will make it easier to install.
 
This has been on my project list for years and it might be on my to-do list even longer.  It’s been working with switches for years so that has a tendency to really slow things down.
 
 
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
  • Member since
    October 2006
  • From: Western, MA
  • 8,571 posts
Posted by richg1998 on Wednesday, April 27, 2016 5:12 PM

You would have to use a DPDT relay to do this with optical detection. To my knowledge, the only way to do this. I have seen this question in various train forums and the same answer and the response is, DPDT switch.

 

Rich

 

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Wednesday, April 27, 2016 2:43 PM

I didn’t know that the auto-reversers used short detection.  I’ve been contemplating building my own using optical detection and relays.  I currently use a home brew detection circuit for warning LEDs on my control panel that light up when turnouts are open to a oncoming train.  I was hoping to find something ready made or in kit form.
 
I went to optical detection because it doesn’t care whether it’s DC, DCC or no power.  
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
  • Member since
    July 2006
  • From: Sebring FL
  • 842 posts
Posted by floridaflyer on Wednesday, April 27, 2016 2:30 PM

agree that there is no easy way to have a DCC reversing section handle both DCC and DC

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Wednesday, April 27, 2016 2:27 PM

DCC autoreverser do not work on DC, so you wither have to make the jump, or continue to use the DPDT toggles. DC, you reverse the main before exiting the loop. DCC, you can do either (which is why the existing DPDT toggles for DC work fine with DCC) - the polarity of the DCC signal does not determine direction of travel. So you can flip the main to match (same as DC) or flip the reverse section right under the moving train (what DCC autoreversers do).

 If the route is always the same, you could repalce teh DPDT toggles with switch machine tontacts, or, better, a relay operated by the switch machine contacts (for higher current capacity and longer life) so that when you throw the turnotu it automatically sets the correct polairty - since it otherwise works the same as the existing DPDT toggles, it will work for DC or DCC. The restrction is that there must be consistent routing through the reverse section. In the more trivial example of your basic loop at the end of a long 'straight' mainline, it woudl mean you always enter the loop to the right and go counter-clockwise, or vice versa - either way, but always the same way in and same way out. Since the turnout has to be changed to allow the train in and out, it works using the contacts. Of course if they are manual turnouts....

                   --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    August 2013
  • From: Richmond, VA
  • 1,890 posts
Posted by carl425 on Wednesday, April 27, 2016 2:05 PM

RR_Mel
I thought that is what I’m looking for, automatic track polarity control.

The auto reverser detects a short when the loco bridges the gap between the main line and the reversing section.  It then reverses the polarity on the reversing section.  This could for DC as you are entering the reversing section, but as you are leaving the reversing section, it again detects the short when you hit the main and reverses the polarity again.  This time because your DC loco is sitting on the reversing section the loco would instantly reverse direction.

I have the right to remain silent.  By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Wednesday, April 27, 2016 1:59 PM

carl425

I don't consider myself a DCC guru, but I can tell you that a DCC auto reverser won't work with a DC loco because they reverse the polarity under the train.

 

I thought that is what I’m looking for, automatic track polarity control.
 
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
  • Member since
    August 2013
  • From: Richmond, VA
  • 1,890 posts
Posted by carl425 on Wednesday, April 27, 2016 1:41 PM

I don't consider myself a DCC guru, but I can tell you that a DCC auto reverser won't work with a DC loco because they reverse the polarity under the train.

I have the right to remain silent.  By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Question for the DCC Gurus
Posted by RR_Mel on Wednesday, April 27, 2016 1:23 PM

This is a simplified drawing of my layout.
 
  
 
I am currently using my original DC block wiring and I operate in both DC and DCC modes using DPDT switches to control my blocks in both modes and I have no problems other than remembering to throw the correct switches.
 
My question is; is there a simple way to go with a DCC type automatic polarity control system that would work in either mode?
 
I have well over 70 locomotives and I only have 12 of them DCC decoder equipped.  I currently operate in DC mode about 75% of the time.
 
 
 
Mel
 
Modeling the early to mid 1950s SP in HO scale since 1951
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!