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Help with proposed crossover in my track plan...

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Posted by mfm37 on Wednesday, October 7, 2009 5:00 PM

Allegheny2-6-6-6

If the train were to travel from the outside loop to the inside loop still continuing in the same direction a reversing loop would or would not be needed?

 

 

There's only one loop (oval actually) with a crossover between the two sides. A train will change direction every time it uses the crossover.

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Posted by Allegheny2-6-6-6 on Wednesday, October 7, 2009 4:24 PM

 One thing has me a little puzzled, would the reversing loop only be required if the train were to change direction correct? If the train were to travel from the outside loop to the inside loop still continuing in the same direction a reversing loop would or would not be needed?

Just my 2 cents worth, I spent the rest on trains. If you choked a Smurf what color would he turn?
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Posted by Phoebe Vet on Wednesday, October 7, 2009 6:10 AM

Dave B:

Maybe it's my fault.  Perhaps I did not make my diagram clear enough.  I don't think you understand where I suggested the OP put his 3 breaks in the track. There is no very short section.  It is not possible for the train to cross two of the breaks without going around one end of the mainline or the other.

If he had drawn a double crossover, it would be different, but he did not.  Check his original diagram.

Dave P

Dave

Lackawanna Route of the Phoebe Snow

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Posted by Phoebe Vet on Tuesday, October 6, 2009 1:49 PM

 Perhaps this diagram is clearer.  The blue side controlled by the auto reverser.  At no time would the train be crossing two transitions at once, and I doubt that he would be running a train longer than the blue section since it appears to be about a third of his mainline.  It WILL work, and you only need ONE reverser.

 

 

Dave

Lackawanna Route of the Phoebe Snow

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Posted by Phoebe Vet on Tuesday, October 6, 2009 1:31 PM

Look more carefully, Dave.  I did not just isolate the crossover.  I divided the track into halves at the crossover.

Other Dave.

Dave

Lackawanna Route of the Phoebe Snow

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Posted by Phoebe Vet on Tuesday, October 6, 2009 12:21 PM

All that is important is that the two sections are completely isolated from each other.  The auto reverse module, when it senses the short as the engine passes across the gap, will reverse the section that it controlls to match the polarity with the one it doesn't control.  It does not matter whether the train is entering or leaving the controlled section.  If the two sections already match, it will not do anything.

I highly recommend Digitrax.  I have the Super Chief.

Dave

Lackawanna Route of the Phoebe Snow

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Posted by gtw1969 on Tuesday, October 6, 2009 11:41 AM

Phoebe Vet

You only need one and yes, you can use other brands.  I showed you that one because you have Bachmann now.  If you follow these posts you are probably aware that I am not a fan of Bachmann.

I prefer, and use, Digitrax, but there are several really good brands available and the choice is a personal preference.

DCC is symmetrical, the engine does not care about polarity.  The auto reverse module is there to prevent short circuits when the track loops back on itself and while the powered units are crossing the boundary between segments where the polarity is reversed.

It works automatically and seamlessly.

Thanks again Phoebe Vet,
I understand where you are coming from about Bachmann. The Dynamis works "ok" for my needs right now and was the cheapest of the bunch. BUT...I can see moving on to Digitrax, MRC, or one of the others down the road.

I have just one more question about this reverse loop thing though...well actually two. (1) It almost seems to me that you need two modules because each end is a reverse loop? (2) are there any special concerns with switch machines controlling the crossover turnouts that I should be aware of?

Steve Rigelhof http://sr-graphics.net
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Posted by Phoebe Vet on Tuesday, October 6, 2009 10:21 AM

You only need one and yes, you can use other brands.  I showed you that one because you have Bachmann now.  If you follow these posts you are probably aware that I am not a fan of Bachmann.

I prefer, and use, Digitrax, but there are several really good brands available and the choice is a personal preference.

DCC is symmetrical, the engine does not care about polarity.  The auto reverse module is there to prevent short circuits when the track loops back on itself and while the powered units are crossing the boundary between segments where the polarity is reversed.

It works automatically and seamlessly.

Dave

Lackawanna Route of the Phoebe Snow

  • Member since
    February 2009
  • From: Warren, MI
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Posted by gtw1969 on Tuesday, October 6, 2009 9:39 AM

Phoebe Vet

 

 install something like this on one of the now isolated loops.

 

Phoebe Vet,
Do I need an auto-reverse module for each side? totalling two modules. Also, I assume I can use other brands besides Bachmann, correct?

Thanks for the help. This seems like a simple solution, assuming it answers my question regarding trains running in either direction as well.

Steve

Steve Rigelhof http://sr-graphics.net
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  • From: Charlotte, NC
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Posted by Phoebe Vet on Tuesday, October 6, 2009 9:27 AM

 

 

Insulate both rails at the joints marked with an X  And then install something like this on one of the now isolated loops.

http://www.hobbylinc.com/htm/bac/bac44912.htm 

 

Dave

Lackawanna Route of the Phoebe Snow

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Posted by BIG JERR on Tuesday, October 6, 2009 8:57 AM

yes I'm curious too, I would guess a reverser but I'm thinking only 1 direction of travel ,but I hope I'm wrong.... some body here knows...J.W.

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Posted by Allegheny2-6-6-6 on Tuesday, October 6, 2009 8:55 AM

 I would imagine a DCC auto reversing module would be all you need. It's been the topic of a few posts lately and exactly how it works I can't say but it does the polarity switching for you. I am only assuming that it some how sense the direction of the locomotive and switches the polarity of the track wiring accordingly.

Here is a link to Tony's trains one of the dcc guru's of the hobby I am sure a better explanation of how it functions can be found there.

 

 

http://www.tonystrains.com/productcompare/dcc_autoreversers_bobd.htm
Just my 2 cents worth, I spent the rest on trains. If you choked a Smurf what color would he turn?
  • Member since
    February 2009
  • From: Warren, MI
  • 55 posts
Help with proposed crossover in my track plan...
Posted by gtw1969 on Tuesday, October 6, 2009 8:47 AM

Hello,
I'm thinking about adding a crossover to my existing layout, but am concerned about "reverse loop" implications. I run all of my trains using DCC only (Bachman Dynamis DCC). Shown in the picture below is a very basic illustration of my mainline with the crossover in question. What components, if any, do I need to make this work so that polarity isn't an issue. I would like to make this as simple as possible with no operator type moves on my end (throwing switches). Is this possible? Will I be able to run trains in either direction to each other if I want and not have worry about anything, other than them crashing into each other?

Thanks for any help you can provide,
Steve


Steve Rigelhof http://sr-graphics.net

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