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Reverse Loops

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  • Member since
    September 2007
  • 55 posts
Reverse Loops
Posted by JGray on Friday, December 12, 2008 8:57 AM

I'm not exactly new to model railroading having done an HO layout about 20 years ago. 

 In my twighlight years, I find myself alone in a  large house and considering going hog wild and pig crazy with N Scale.

I purchased one of the model railroad CAD's and have designed a number of layouts concentrating mainly on operations.  Having finally chosen one I would like to build, I have one main concern.

The trackwork I have settled on has a number of reverse loops.  I would never have considered this 20 years ago, but I have read that DCC handles these.  Therein lies the last concern I have before beginning construction.  Can DCC indeed handle reverse loops?  If so, is there anything special I need to be aware that I can learn without frying components on down the road somewhere?

Thanks

Jim

  • Member since
    July 2003
  • From: Sierra Vista, Arizona
  • 13,757 posts
Posted by cacole on Friday, December 12, 2008 9:28 AM

Reverse loops are a problem with DCC just the same as they are with DC; however, with DCC you can get auto-reverse modules instead of having to flip a bunch of toggle switches.

With DCC you're reversing the phase of the DCC command signal, not polarity.  In my opinion, the best option is a totally electronic reverse module such as those sold by Tony's Train Exchange instead of one that uses a mechanical relay.

Something you may find useful is the "DCC Primer" on Tony's web site.  Near the bottom of the index page is a chapter on Reverse Loops.  At the top of the page are options to download the entire publication so you can view it offline or print a copy using Acrobat Reader.

http://www.tonystrains.com/tonystips/dccprimer/index.htm 

 

  • Member since
    November 2007
  • 1,089 posts
Posted by BlueHillsCPR on Friday, December 12, 2008 9:35 AM

Here is a quote from Allan Gartners Wiring for DCC

"

There are three basic things you must do when you wire a reversing section.

1. Make sure the reversing section is at least as long as your longest train. If you are not using any lighted cars, the reversing section only needs to be longer than the locomotive.

2. Double gap the track at both ends of the reversing section.

3. Do not connect your main bus to your reversing section in any way. Your reversing section must only be connected to your reverse section controller, reversing relay, or reversing switch.

Be sure to follow the diagrams in this webpage or the instructions for your reverse section controller carefully."

Wiring For DCC

 

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,348 posts
Posted by MisterBeasley on Friday, December 12, 2008 11:32 AM

Allen Gartner wrote:
If you are not using any lighted cars, the reversing section only needs to be longer than the locomotive.

"Lighted Cars" is a very bad way to express this condition.  A simple gap can be bridged by a single metal wheel, regardless of whether the car has lights.  A slightly longer gap can be bridged by a pair of wheelsets connected to a metal truck.  And you certainly don't want a gap that long, anyway.

To be even more fussy, the "Easy Peasy" lighting kits for passenger cars are battery powered, so they don't connect to the wheels at all.

The only way I would accept this statement is to change it to:  "If you are only using rolling stock with plastic wheels, the reversing section only needs to be longer than the locomotive."

It takes an iron man to play with a toy iron horse. 

  • Member since
    November 2007
  • 1,089 posts
Posted by BlueHillsCPR on Friday, December 12, 2008 12:48 PM

Mr. B.

I agree the wording leaves room for problems.  However if you will notice, I did say it was a quote from ALLAN GARTNERS WIRING FOR DCC, so perhaps you should take it up with him rather than quoting it as though I said it and chastising me for his error in wording. Smile,Wink, & Grin

Rivet counters! Whistling

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,348 posts
Posted by MisterBeasley on Saturday, December 13, 2008 2:18 PM

Sorry, I didn't mean to shoot the messenger.  I updated my post to indicate the original author.

It takes an iron man to play with a toy iron horse. 

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