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Reverser questions

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  • Member since
    September 2002
  • 7,120 posts
Reverser questions
Posted by ndbprr on Tuesday, July 27, 2021 6:41 PM

Dogbone staging yard probably 6 tracks to a two track main.  T here will be several locations where swtchers will need to crossover to industries so it makes sense to have both mains with the same polarity and switch the loops. Simplest way I can come up with is either at the ends or split the loops into halves because it might be possible to have a train entering and another leaving at the same time causing circuit switching problems.  How should I do this the correct way?

  • Member since
    June 2020
  • 3,011 posts
Posted by Lastspikemike on Tuesday, July 27, 2021 7:32 PM

It may help to think of each possible reversing section as just a Block. Thinking in terms of loops and mains can distract from the electrical problem which is simply matching polarity (phase ) across adjoining Blocks. You just fit reversing switches wherever that problem exists.

When you switch polarity in one DCC powered Block nothing untoward happens. The polarity (phase actually) needs to match as the train is occupying more than one Block. Separate polarity control is required for any two adjoining Blocks that may be occupied by one train with metal wheels at both ends. Whether these loops or main lines are considered main or reversing section matters not. It's the relative polarity (phase) between adjoining sections occupied by one train that needs to be controlled.

For DC it is obvious when done incorrectly because the polarity control must change the polarity in the Block with no train in it.  If you get it wrong a train reverses unexpectedly (although predictably when you think it through). For DCC it isn't as complicated. 

Alyth Yard

Canada

  • Member since
    September 2004
  • From: Dearborn Station
  • 21,722 posts
Posted by richhotrain on Tuesday, July 27, 2021 8:43 PM

ndbprr

Dogbone staging yard probably 6 tracks to a two track main.  T here will be several locations where swtchers will need to crossover to industries so it makes sense to have both mains with the same polarity and switch the loops. Simplest way I can come up with is either at the ends or split the loops into halves because it might be possible to have a train entering and another leaving at the same time causing circuit switching problems.  How should I do this the correct way? 

On my layout, a double mainline dogbone with both mainlines running parallel to themselves (per diagram) with a series of four double slips, between the end loops, I treated the sections of track immediately adjacent to the "4-track mainline" as reversing sections. So, I had four reversing sections, each long enough to accomodate the longest train.

The diagram that follows illustrates this arrangement with the reversing sections in red. All of the track in blue is part of the non-reversing section of the layout.

Rich

4-Track-Mainline.jpg

Alton Junction

  • Member since
    July 2021
  • 1 posts
Posted by CARLAO on Thursday, July 29, 2021 8:00 AM

In my case, I have an Helix, my doubt , and that if Helix, causes polarity inversion in DCC?
Another question, and that AR-1 Digitrax, has capacity for more than one LOOP?I have 02 loops and a Helix.
Thank you

  • Member since
    September 2004
  • From: Dearborn Station
  • 21,722 posts
Posted by richhotrain on Tuesday, August 3, 2021 6:20 AM

What happened with our OP?

Rich

Alton Junction

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