Date   

Import Conversation

 

Hello Allan,
I posted the topic "Offset Rail Gapping" both here and at the NCE-DCC@groups.io site. On that site Bruce Petrarca generalized the discussion to "Rail Gaps" and the discussion really took off with many very interesting inputs by some of the most knowledgeable people, on the topic, that I know. Is it possible to import the conversation to this site so that members of this site could benefit?
As always,
Michael Boyle


Re: Offset Rail Gapping

prandn
 

RealWorldApplication ... joints in rails are ALWAYS* parallel to each other, a practice also required in model railroading.... 🙃

Now the staggering of joints is a completely different subject......

* Exception: when a “ sun-kink “ or derailment or some other phenomenon has caused the rails to become unparallel.....

loren martell
Aloha, OR 97007


Re: Twisting Wires

Mark Gurries
 

A twisted cable is defined as pair of wires twisted together with each other AND carrying the same signal/power/current going out and back.

Twisting random wires together that have nothing to do with each other will potentially create problems because the noise in one wire will become coupled to the other wire. -Or- Two signal that have nothing to do with each will interfere with one another.

Hence a cable with multiple wires that have different purposes but collectively contain in a single multiwire cable where they all follow one big twist together does NOT qualify as a twisted cable.


On Mar 23, 2020, at 5:54 PM, Carl <carl.blum@...> wrote:

Hello Charles:

These are not communication cables, just industrial control cables. They are cool the way they are arranged: a green/yellow ground in the center and then numbered wires starting at "1" radiating around the ground. So with ground there are 7, 13, 37 conductors. Some cables have place holding fillers to stack nicely. I think the whole cable does twist, but very slowly, perhaps one turn every 2 meters.

Carl.

On 3/23/2020 3:57 PM, Charles Brumbelow via Groups.Io wrote:
Your industrial cables may already be twisted. CAT 5 Ethernet cable uses twisted pairs inside the plastic jacket, for example. 

Charles




On Monday, March 23, 2020, 1:32 PM, Carl <carl.blum@...> wrote:

Hi Gang:

Here is a question about twisting the bus wires. Would it work to twist the wires after they are installed? Like a tourniquet, put a stick at the mid point and start twisting. Like this:

=/////////|\\\\\\\\\\=

Sure one side would be clockwise and the other counter clock wise. I think the telephone company did flip their wires every ten poles or so.

I didn't twist anything and the layout runs OK. But if I had problems this might help. ( For me it would be hard, I used 10 conductor industrial cables )

I did add a snubber to Ruth Mountain, the longest wire run.

Thanks, Carl.



Best Regards,

Mark Gurries
Electrical Engineer
DCC Website & NMRA DCC Clinics: www.markgurries.com




Re: Twisting Wires

Carl
 

Hello Charles:

These are not communication cables, just industrial control cables. They are cool the way they are arranged: a green/yellow ground in the center and then numbered wires starting at "1" radiating around the ground. So with ground there are 7, 13, 37 conductors. Some cables have place holding fillers to stack nicely. I think the whole cable does twist, but very slowly, perhaps one turn every 2 meters.

Carl.

On 3/23/2020 3:57 PM, Charles Brumbelow via Groups.Io wrote:
Your industrial cables may already be twisted. CAT 5 Ethernet cable uses twisted pairs inside the plastic jacket, for example. 

Charles




On Monday, March 23, 2020, 1:32 PM, Carl <carl.blum@...> wrote:

Hi Gang:

Here is a question about twisting the bus wires. Would it work to twist the wires after they are installed? Like a tourniquet, put a stick at the mid point and start twisting. Like this:

=/////////|\\\\\\\\\\=

Sure one side would be clockwise and the other counter clock wise. I think the telephone company did flip their wires every ten poles or so.

I didn't twist anything and the layout runs OK. But if I had problems this might help. ( For me it would be hard, I used 10 conductor industrial cables )

I did add a snubber to Ruth Mountain, the longest wire run.

Thanks, Carl.



Re: Twisting Wires

Charles Brumbelow
 

Your industrial cables may already be twisted. CAT 5 Ethernet cable uses twisted pairs inside the plastic jacket, for example. 

Charles




On Monday, March 23, 2020, 1:32 PM, Carl <carl.blum@...> wrote:

Hi Gang:

Here is a question about twisting the bus wires. Would it work to twist the wires after they are installed? Like a tourniquet, put a stick at the mid point and start twisting. Like this:

=/////////|\\\\\\\\\\=

Sure one side would be clockwise and the other counter clock wise. I think the telephone company did flip their wires every ten poles or so.

I didn't twist anything and the layout runs OK. But if I had problems this might help. ( For me it would be hard, I used 10 conductor industrial cables )

I did add a snubber to Ruth Mountain, the longest wire run.

Thanks, Carl.



Twisting Wires

Carl
 

Hi Gang:

Here is a question about twisting the bus wires. Would it work to twist the wires after they are installed? Like a tourniquet, put a stick at the mid point and start twisting. Like this:

=/////////|\\\\\\\\\\=

Sure one side would be clockwise and the other counter clock wise. I think the telephone company did flip their wires every ten poles or so.

I didn't twist anything and the layout runs OK. But if I had problems this might help. ( For me it would be hard, I used 10 conductor industrial cables )

I did add a snubber to Ruth Mountain, the longest wire run.

Thanks, Carl.



Re: Wiring a Yard

Tim
 

For that situation, the most important thing is keeping things organized. Consistent color coding is vital. Then come up with a sensible approach and stick with it.

Tim Rumph
Lancaster, SC


Re: Wiring a Yard

dsabourne
 

I use the following online calculator for my wire sizing needs.

David

http://wiresizecalculator.net/


Re: Offset Rail Gapping

mgj21932
 

David,
Now that answer makes sense.
Bill D

On Monday, March 23, 2020, 11:18:20 AM EDT, dsabourne via Groups.Io <dsabourne@...> wrote:


This is a real world application ... where you never have joints in rails parallel to each other.  Not a practice required in model railroading.

-David


Re: Offset Rail Gapping

dsabourne
 

This is a real world application ... where you never have joints in rails parallel to each other.  Not a practice required in model railroading.

-David


Re: Offset Rail Gapping

dsabourne
 

This is a real world application ... where you never have joints in rails parallel to each other.  Not a practice required in model railroading.

-David


Re: Wiring a Yard

Don Vollrath
 

It’s not that critical. One direction only. Estimate from beginning to end or Use a tape measure. 

DonV


Re: Offset Rail Gapping

PennsyNut <pennsynut@...>
 

The only place where offsetting might be warranted is in curves where you do not solder. The better way is to solder all rails in a curve. In fact, even turnouts in a curve should be soldered to the track next to them. But as has been stated above, staggered joints don't really make a lot of sense. Just MHO.
Morgan Bilbo, about one year with very basic DCC


Re: Wiring a Yard

 

Thank you,
But what about the second part of the questions? How do we calculate the length of a track bus?
-Michael


Re: Wiring a Yard

wirefordcc
 

This topic is a good time to let new readers know about the work I did on track feeder size.  The results are on my website at:

http://www.wiringfordcc.com/track_2.htm#a14

There you will find a table of feeder sizes and feeder lengths that I tested .  My objective was to determine if a booster would trip or not.  I can definitely say do not use feeder sizes and lengths that are in the orange or red zones as your booster will not reliably trip.  

No matter what, after installation, short your track with a metal tool or object aka "the quarter test" to make sure your booster trips reliably.  Perform this test at the farthest point on a section of track from which the feeder attaches.  If its not going to work, you want to find out now.

Allan Gartner
Wiring for DCC


Re: Wiring a Yard

Jerry Michels
 

Michael,this is a great question.  I believe the length of the longest run is the answer.  Parallel busses should not affect the available power.

Jerry Michels
Amarillo Railroad Museum


Re: Offset Rail Gapping

Jerry Michels
 

Michael, As far as I know, it is a way to avoid having a weak point where track could shift/kink out of alignment, especially on curves.  If used at all, the offset can be small.  If your track is properly installed and securely glued down, I do not think on offset is needed.  Consider that in almost every situation, when track is attached to a turnout the joints are not offset.  That being said, we have not found a problem having an offset with DCC.  We have some old-school members who insisted on having offsets, but in truth have suffered no ill effects either way.

Jerry Michels
Amarillo Railroad Museum


Re: Wiring a Yard

Don Vollrath
 

Michael et al
If you are not providing isolated yard tracks with any power cut off switches then each track is merely another parallel path for the DCC power to flow.... just like that on the track rails. Don’t worry so much about the wiring underneath. Provide a single main DCC bus to follow the main/center layout of the yard tracks from end to end while continuing onto the mainlines. Use multiple 20 AWG track feeders to connect each yard track to the same DCC bus. (24 gauge is kinda small) solder rail joiners or provide track drops for each section of track. Allow for some rail expansion movement to prevent kinking.

Calculate DCC bus length as if it were a single conductor. Avoid forming it into a loop. Add an R/C snubber at the ‘open’ end far away from the booster.

DonV


Re: Offset Rail Gapping

whmvd
 

Michael,

I've read it too, and have followed several threads in various forums on this subject. I have never found an explanation for the practice that made sense to me, but people can get almost religious on this topic, so prepare for heated argument!

Wouter


On Sun, 22 Mar 2020 at 02:18, Michael Boyle <boyle10017@...> wrote:
Greetings,
I've read, and been told, to offset the rail gaps between power districts. What is the science behind this and do we do that everywhere (for example in a reversing loop)?
Thanks,
Michael


Re: Offset Rail Gapping

Don Vollrath
 

It’s hearsay BS. No science behind it. Never seen a case where staggered gaps are required when other recommended practices are Being followed. Put isolating gaps opposite each other. Fill the gaps so they cannot close by rail movement.
DonV

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