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!

How Do I Handle the End of A Dogbone?

8534 views
47 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    July 2013
  • 245 posts
Posted by starman on Monday, January 2, 2017 8:23 PM

For those who are interested, I have decided to simplify things by rearranging my pike so I can run a double main line.  I actually have enough track on hand to do this and it will eliminate the need for me to have reversing loops, not to mention saving dollars!

My pike takes up a basement room that is 19' by 13'.  I am attempting to model the Norfolk and Western coal operation of the 1950's from western Virginia to the Lambert's Point yard in Norfolk, Virginia.  I have a 24" wide shelf on 3 walls and part of 1 wall.  The ends of the shelves flair out to accommodate about a 30” radius track.  I also have a 5' wide peninsula running down the center of the room.  On the peninsula will be my interpretation of the Norfolk and Western Lambert's Point yard where coal from western Virginia is loaded onto colliers for sea transport to other ports.  (I grew up just a few miles from the Lambert's Point yard.)

If all goes as planned, I should have about 130' of main line circling the entire pike.  My smallest radius will be about 30”.  I am using DigiTrax.  We have an N&W J Class engine, 2 other steam engines, and several early diesel engines, plus an assortment of rolling stock.  The J Class and the other steam engines have already been converted to DCC.  Hopefully the diesels will be converted soon.

My son and I are building this pike mainly for his children (7 & 5).  My son remembers the simple pike my father had when my son was young and has always wanted his own pike.  I have the room so we are building the pike in my basement.  My son lives very close by.

 

 
  • Member since
    September 2014
  • From: 10,430’ (3,179 m)
  • 2,311 posts
Posted by jjdamnit on Monday, January 2, 2017 12:57 PM

Hello all,

You have not said how big the layout will be or the radius of the loops.

Is this a shelf layout?

A stand alone pike?

Will this be a walk around or against a wall?

Is this a display that is autonomous or will a person be operating the pike?

All good things to know.

One other thing to consider; with the single track main, is that the loops on the ends of the dog bone will determine the maximum length of the train.

Also, the radius of the track can also limit the type of motive power and rolling stock.

An 18-inch radius might limit you to 4-axle diesels, 0-4-0 and/or 0-6-0 steamers and a maximum of 50-foot rolling stock.

Please keep us in "the loop" so to speak!

Hope this helps.

 

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

  • Member since
    March 2015
  • 1,358 posts
Posted by SouthPenn on Monday, January 2, 2017 10:36 AM

There are gaps at the main route and diverging route. The polarity of the loop track is controlled by the PSX-AR.

South Penn
  • Member since
    August 2013
  • From: Richmond, VA
  • 1,890 posts
Posted by carl425 on Monday, January 2, 2017 10:17 AM

gregc
a train will enter the loop through the same turnout position it last exited the loop?

Yes.

The polarity is always correct for the direction the turnout is aligned.  Left alone, every other trip through the loop will be in the opposite direction.

There is also an option to manually reverse the loop.  This will also throw the turnout so you can go around in the other 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
    July 2009
  • From: lavale, md
  • 4,678 posts
Posted by gregc on Monday, January 2, 2017 9:33 AM

aren't the gaps on the diverging side (loop) side of the turnout.   I can see how this works when the train is exiting the loop, if the turnout switches quickly.  

But what about a train entering the loop.  won't it be over the turnout?   Or is it expected that the turnout is only controlled by the reverser?  that a train will enter the loop through the same turnout position it last exited the loop?

greg - Philadelphia & Reading / Reading

  • Member since
    March 2015
  • 1,358 posts
Posted by SouthPenn on Monday, January 2, 2017 9:14 AM

The switch machine is wired directly to the PSX-AR. When the PSX-AR detects a short at one of the gaps at the end of the reverse loop, it throws the switch and reverses the track polarity. The engine just keeps moving through the switch like nothing happened.

PSX-AR instructions.

South Penn
  • Member since
    July 2009
  • From: lavale, md
  • 4,678 posts
Posted by gregc on Monday, January 2, 2017 8:56 AM

i'm curious, how does the PSX control the turnout?

greg - Philadelphia & Reading / Reading

  • Member since
    February 2003
  • From: Morristown, NJ
  • 812 posts
Posted by nealknows on Monday, January 2, 2017 7:55 AM

carl425

The PSX-AR will handle your polarity reversing and automate the turnout for you.

 

I second the use of the PSX-AR. Very easy to use. 

Neal

  • Member since
    March 2015
  • 1,358 posts
Posted by SouthPenn on Sunday, January 1, 2017 7:58 PM
South Penn
  • Member since
    September 2014
  • From: 10,430’ (3,179 m)
  • 2,311 posts
Posted by jjdamnit on Sunday, January 1, 2017 7:33 PM

Hello all,

Please let us know which solution you decided on and keep us informed on your progress.

Thanks for sharing.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

  • Member since
    December 2016
  • 168 posts
Posted by speedybee on Sunday, January 1, 2017 7:18 PM

If you are willing to jump onto the Arduino train, reversing loops (and most anything else) can be done quite easily and cheaply!

  • Member since
    July 2013
  • 245 posts
Posted by starman on Sunday, January 1, 2017 7:08 PM

carl425

The PSX-AR will handle your polarity reversing and automate the turnout for you.

 

Thanks for the information.  I will look into a PSX-AR.

  • Member since
    August 2013
  • From: Richmond, VA
  • 1,890 posts
Posted by carl425 on Sunday, January 1, 2017 6:43 PM

The PSX-AR will handle your polarity reversing and automate the turnout for you.

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
    July 2013
  • 245 posts
Posted by starman on Sunday, January 1, 2017 5:25 PM
HTH
Thanks for your comments.  I have DigiTrax that I will be using.  I am new to DCC.  My reason for only using one main line is there are sections where I don’t have the room to lay double tracks.  As I am now in the process of building my pike, it is not too late to make some changes so I can perhaps lay a double track.  Maybe I will do just that.  However, do you have a specific reference for what I would need and how to wire for automatic switching?  Thanks again!

 

Starman
  • Member since
    September 2014
  • From: 10,430’ (3,179 m)
  • 2,311 posts
Posted by jjdamnit on Sunday, January 1, 2017 4:59 PM

Hello all,

Yes, you can switch the turnout and the polarity automatically. 

Again, are you using DC or DCC?

If you are using DC Atlas makes units that will switch the turnout and the polarity automatically. Snap Relays.

As I said before this will add complexity and cost to your layout.

If you are using DCC automatic switching and polarity reversing can be accomplished. Again, with additional cost and complexity.

starman, my question to you is, why don't you just add a second mainline?

This will decrease complexity and cost no matter what system you use.

The cost of the extra track will be significantly less than adding automation to your pike.

Your choice.

The solution you are seeking can be done through automation and cost.

Hope this helps.

Post Script: I suggest you get the Atlas Complete Wiring Book. This primarily deals with DC wiring but has applications and concepts the are pertinent to DCC applications. Also, Kalmbach Publishing has several DCC specific books that can help you in your track plan and wiring decisions.

H.T.H.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

  • Member since
    July 2013
  • 245 posts
Posted by starman on Sunday, January 1, 2017 4:30 PM

gregc

 

 
starman
If I use a turnout, I will have to switch the turnout each time the train comes out of the loop.  I am hoping I won’t have to do that.

 

not sure why you question the use of a turnout?   Of course you'll need one since the track loops back to itself.   And you'll need to switch the turnout after the train enters the loop.  Are you thinking the turnout can be switched automatically?

typical dogbone

 

I was hoping I could switch the turnout automatically, but perhaps that is not possible.

  • Member since
    September 2014
  • From: 10,430’ (3,179 m)
  • 2,311 posts
Posted by jjdamnit on Sunday, January 1, 2017 3:57 PM

Hello all,

the only way to avoid a turnout or switch is to create a dual track main between the two ends of the bone.

This will eliminate the need for an auto-reversing unit as the polarity remains the same through out the track loop.

Other than that, there is no way to avoid switches and an auto-reversing unit.

Don't forget the gaps for the AR unit.

You can automate the switching actions by using detection units but that will add cost and complexity to the wiring of your pike.

Also, you did not mention if you are using DC or DCC. With DC you can activate the switch and the polarity with a Double Pole Dual Throw switch.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

  • Member since
    July 2009
  • From: lavale, md
  • 4,678 posts
Posted by gregc on Sunday, January 1, 2017 3:36 PM

starman
If I use a turnout, I will have to switch the turnout each time the train comes out of the loop.  I am hoping I won’t have to do that.

not sure why you question the use of a turnout?   Of course you'll need one since the track loops back to itself.   And you'll need to switch the turnout after the train enters the loop.  Are you thinking the turnout can be switched automatically?

typical dogbone

greg - Philadelphia & Reading / Reading

  • Member since
    July 2013
  • 245 posts
How Do I Handle the End of A Dogbone?
Posted by starman on Sunday, January 1, 2017 1:54 PM
I am laying track on my HO layout.  I have a dog bone type layout.  I have a single single track going into a loop at one end.  The train then comes out of the loop, in the opposite direction, and goes back onto my single track.  What type of track arrangement do I use where my single track goes into my loop? I plan on using an AR1 to handle the current.  If I use a turnout, I will have to switch the turnout each time the train comes out of the loop.  I am hoping I won’t have to do that.  Thanks for your time and help.

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!