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Wiring a Double Crossover for DC

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Wiring a Double Crossover for DC
Posted by Neptune48 on Tuesday, November 24, 2020 12:38 PM

It may be too late to ask, as last night I woke up and decided to shut down the hobby until further notice, but I am still curious about the final nail in my model railroad coffin: wiring a double crossover for DC.

The plan was to use four Tortiose switch machines (easier, and I think cheaper than rigging a mechanical linkage and using only two machines), using one switch in each machine to power the frog for each turnout.  The other switch in each machine was to drive signal logic.

The tricky part was how to to route power to the dimond to follow the turnout configuration.  Mostly I managed to confuse myself thoroughly, but I can't figure any solutions that don't involve a very expensive 8-ganged 3-position rotary switch or relays, neither of which generates much enthusiasm on my part.  This is as far as I got:

Double Crossover Partial Wiring

I think I have the gaps correct, but I'm not absolutely certain of anything:

Diamond_Closeup

This must have been solved long ago by people much smarter than me, but the only solutions I can find online involve DCC and frog juicers, and now I'm ready to chuck it all and put a bunch of stuff up on ebay.

So how do they do it?

Thanks,
Bruce

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Posted by RR_Mel on Tuesday, November 24, 2020 1:22 PM

I couldn’t get any code 83 manufactured double crossovers to pass my pizza cutter flange Rivarossi articulateds without shorting so I built my own from code 83 Atlas Custom Line #6 turnouts and a 19° Atlas crossover.

I didn’t do any special gaping or wiring.  I did add wires to the four frogs but none of my locomotives had any problems so I didn’t need to power the frogs.

I couldn’t see any reason for not throwing all four turnouts together so I went with a single Tortoise and connecting rods to change all four with one switch machine.



My double crossover has worked flawlessly for eight years.



I used one set of Tortoise contacts to feed my signaling system and use by-color LEDs in series with the Tortoise for turnout position.

I might add I operate my layout dual mode, DC or DCC, and my double crossover is simply connected rail to rail, no gaps no problems in either mode.

https://melvineperry.blogspot.com/2012/06/june-25-2012-my-double-crossover.html

Mel



 
My Model Railroad   
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Posted by Neptune48 on Tuesday, November 24, 2020 4:10 PM

Thanks for your quick response, Mel.  I'm going to study this material and see if I can wrap my alleged mind around it.

It won't surpirse me at all to learn I'm overthinking this.

Regards,
Bruce

 

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Posted by RR_Mel on Tuesday, November 24, 2020 4:31 PM

I tried a Fast Track Double Crossover and it would pass my large flange Rivarossi articulateds but when I saw the complex wiring I said No Way!!  I was in electronics my entire 50 year working career and that wiring was a joke!  There was no way I was going to get that complicated on my layout!!!!  Its model railroading not a complicated wiring project.

I sold the Fast Track on eBay and got what I paid for it less my labor for assembling it.  It was worth the experience to find out how ridicules model railroading can get if you let it.

Regular Atlas Custom Line turnouts will work fine configured with the 19° crossover without any special wiring or gaping.  You can throw the turnouts with anything that will work I decided to go with one Tortoise for economy.  I couldn’t see why all four turnouts couldn’t be powered from one switch machine.  The double crossover can only handle one train at a time so it doesn’t make sense to go to the expense for multiple switch machines.  It might not be prototypical but I’m not a rivet counter either.

Don’t give up, it’s a great hobby!!!!
 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

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Posted by ATLANTIC CENTRAL on Tuesday, November 24, 2020 5:04 PM

Well Bruce, it would be helpful to konw how you plan to control the rest of the layout, or what the track plan is, to know what is best.

But Mel has great info for you to start with.

Not sure about your frustration with the hobby........

I have been at this since 1968, I still use DC, and yes you are over thinking this.

What brand of turnouts or is it a complete double crossover like Walthers?

If you really want some help, let me know, or let Mel know, there is plenty of help available.

This hobby is technical, it is not for everyone, but if master the basics, you will find one of the most diverse and rewarding hobbies in the world.

Sheldon

    

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Posted by MisterBeasley on Tuesday, November 24, 2020 5:19 PM

Yeah, sometimes it's just a matter of doing it.  I had never used one Tortoise to control two turnouts, but the linkages from Circuitron were cheaper than another Tortoise, although not by much.  Besides that, I was controlling a pair of crossing gates, so I figured I could do it.  In that cramped space, I think it was actually easier.

So much stuff is so much easier to just get done than analyzing it until you conclude it's impossible.

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

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Posted by RR_Mel on Tuesday, November 24, 2020 6:34 PM


Both tracks are essentially in the same electrical block so no shorts using the Atlas crossing.  I can kill power to either main line but always powered from the same throttle source.  

My layout is wired for DC operation and works great on either DC or DCC, no DCC Buss wiring.  I rewired my layout to the accepted DCC Guru way when I first went with DCC and it screwed up everything on my layout.  After 6 months of screwing around with the Guru way I ripped out the Buss wiring and rewired it back to my original DC Block Wiring.  It has worked flawlessly with my wiring back to the original DC wiring.

My Mel double crossover works perfectly without gaps on DC or DCC. The Atlas Custom Line #6 frogs don’t need to be powered for my locomotives, my shortest locomotive is a MDC 0-6-0 and they work great going through all my Atlas non powered frogs.
 

Mel



 
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Posted by ATLANTIC CENTRAL on Tuesday, November 24, 2020 9:42 PM

Lastspikemike

There can be a problem with the crossing (diamond)  if it is possible for each of two throttles to power different tracks on the crossing simultaneously. I inadvertently discovered this when I left the power from one DC powerpack on to a switched on block with no locomotive on the crossing track  while I operated a train across the other line of the crossing using the second DC powerpack. Sure enough I saw the flashes as the frogs shorted. Peco 120 degree crossing, no turnouts. My solution will be to wire a Peco microswitch to switch one pole of each powered track so that only one crossing track has power at one time. The nearest turnout to the crossing will operate that polarity switch. It will operate just as a frog polarity control switch would work.

The crossing connects a yard access track to an engine yard on the "other side" of the mainline track. By controlling power in this way collisions will also be avoided. Up to now we have only used Manuel control and he obviously forgot to power off that crossing block, as Manuel is prone to do being only human after all. 

Now,  I have only a crossing and not a slip switch. Slip switches might be trickier to wire in this manner. 

I'm pretty sure this shorting would be enough to punt out a DCC booster so we need to fix this before we go DCC.

 

I can't speak for a PECO crossing, but if I am understanding you, that would not happen with an Atlas crossing.

Kind of like the turnout frog "problem" in the other thread. Bad design to have such small isolation gaps at crossing or turnout frogs......

Sheldon

    

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Posted by Neptune48 on Tuesday, November 24, 2020 11:27 PM

RR_Mel
RR_Mel wrote the following post 6 hours ago: I tried a Fast Track Double Crossover and it would pass my large flange Rivarossi articulateds but when I saw the complex wiring I said No Way!! I was in electronics my entire 50 year working career and that wiring was a joke! There was no way I was going to get that complicated on my layout!!!! Its model railroading not a complicated wiring project. I sold the Fast Track on eBay and got what I paid for it less my labor for assembling it. It was worth the experience to find out how ridicules model railroading can get if you let it. Regular Atlas Custom Line turnouts will work fine configured with the 19° crossover without any special wiring or gaping. You can throw the turnouts with anything that will work I decided to go with one Tortoise for economy. I couldn’t see why all four turnouts couldn’t be powered from one switch machine. The double crossover can only handle one train at a time so it doesn’t make sense to go to the expense for multiple switch machines. It might not be prototypical but I’m not a rivet counter either. Don’t give up, it’s a great hobby!!!! Mel My Model Railroad http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.

That's ominous, Mel.  I had hoped to use Fast Track, but I'll have to revisit that.

Thanks,
Bruce

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Posted by Neptune48 on Tuesday, November 24, 2020 11:58 PM

ATLANTIC CENTRAL

Well Bruce, it would be helpful to konw how you plan to control the rest of the layout, or what the track plan is, to know what is best.

But Mel has great info for you to start with.

Not sure about your frustration with the hobby........

I have been at this since 1968, I still use DC, and yes you are over thinking this.

What brand of turnouts or is it a complete double crossover like Walthers?

If you really want some help, let me know, or let Mel know, there is plenty of help available.

This hobby is technical, it is not for everyone, but if master the basics, you will find one of the most diverse and rewarding hobbies in the world.

Sheldon

 
I'll try to keep this as brief as possible.
Based on my childhood love of UP Streamliners and one glorious summer spent as a switchman/brakeman out of the UP East [Los Angeles] Yard, here are my design criteria:
  • Extremely limited space: 3’–9” x 5’–10”
  • N Scale
  • DC Control
  • 2ea MRC throttles, to be replaced by scratch-built TAT V Walk-Around Throttles
  • Continuous mainline running for the unwashed
  • Switching for me
  • Hand-laid Track, using Fast Tracks Code 55 or Code 70 Rail
  • ABS type signaling, controlled by PIC microcontrollers
Space prohibits much scenery, crossings, helixes, etc.  It’s just a simple double-track loop with way too much track for the area.  Indeed the working name for this railroad is Spaghetti Bowl & Pacific.
This will be a free-standing tabletop layout.  Mainline turnouts will have Tortoise switch machines.  Yard and industry switches will use ground throw controls.
 
Mainline minimum radius:                         17â…œ” with easements and slight superelevation.
Yard and industry minimum radius:         14½”
    Floor Plan             
Room Floor Plan
Track Plan
Track Plan
Control Panel
Panel Layout
Is this sufficient information?
Thanks,
Bruce
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Posted by Neptune48 on Wednesday, November 25, 2020 12:09 AM

Thanks, MisterBeasley.

I tend to overplan to compensate for lack of skill and talent.  I thought about using two Tortises for each crossover, but I think the space constraints and figuring out the rigging is more trouble than just buying four Tortoises per.

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Posted by Neptune48 on Wednesday, November 25, 2020 12:35 AM

Lastspikemike

There can be a problem with the crossing (diamond)  if it is possible for each of two throttles to power different tracks on the crossing simultaneously. I inadvertently discovered this when I left the power from one DC powerpack on to a switched on block with no locomotive on the crossing track  while I operated a train across the other line of the crossing using the second DC powerpack. Sure enough I saw the flashes as the frogs shorted. Peco 120 degree crossing, no turnouts. My solution will be to wire a Peco microswitch to switch one pole of each powered track so that only one crossing track has power at one time. The nearest turnout to the crossing will operate that polarity switch. It will operate just as a frog polarity control switch would work.

The crossing connects a yard access track to an engine yard on the "other side" of the mainline track. By controlling power in this way collisions will also be avoided. Up to now we have only used Manuel control and he obviously forgot to power off that crossing block, as Manuel is prone to do being only human after all. 

Now,  I have only a crossing and not a slip switch. Slip switches might be trickier to wire in this manner. 

I'm pretty sure this shorting would be enough to punt out a DCC booster so we need to fix this before we go DCC.

 

Lastspikemike,

This is what I'm concerned about.  Using several copies of the crossover drawing, I color-coded each rail to determine where power would be needed and where shorts might be a problem.

Scenarios

I once built a TAT IV years ago, and I really like how it operated.  It didn't survive the move, and components are so obsolete now I've based my design on the TAT V.  I haven't yet seen a DCC system that emulates the same action as the TAT, and I find adding DCC receivers to N-Scale locos expensive and daunting.  Therefore, I doubt I'll ever leave the DC world.

Thanks,
Bruce

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Posted by Neptune48 on Wednesday, November 25, 2020 12:38 AM

RR_Mel


Both tracks are essentially in the same electrical block so no shorts using the Atlas crossing.  I can kill power to either main line but always powered from the same throttle source.  

My layout is wired for DC operation and works great on either DC or DCC, no DCC Buss wiring.  I rewired my layout to the accepted DCC Guru way when I first went with DCC and it screwed up everything on my layout.  After 6 months of screwing around with the Guru way I ripped out the Buss wiring and rewired it back to my original DC Block Wiring.  It has worked flawlessly with my wiring back to the original DC wiring.

My Mel double crossover works perfectly without gaps on DC or DCC. The Atlas Custom Line #6 frogs don’t need to be powered for my locomotives, my shortest locomotive is a MDC 0-6-0 and they work great going through all my Atlas non powered frogs.
 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

 

 

Do the Atlas crossing or the switches have non-conducting sections, such as insulated frogs?

Thanks,
Bruce

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Posted by ATLANTIC CENTRAL on Wednesday, November 25, 2020 5:26 AM

 

Neptune48

 

 
RR_Mel


Both tracks are essentially in the same electrical block so no shorts using the Atlas crossing.  I can kill power to either main line but always powered from the same throttle source.  

My layout is wired for DC operation and works great on either DC or DCC, no DCC Buss wiring.  I rewired my layout to the accepted DCC Guru way when I first went with DCC and it screwed up everything on my layout.  After 6 months of screwing around with the Guru way I ripped out the Buss wiring and rewired it back to my original DC Block Wiring.  It has worked flawlessly with my wiring back to the original DC wiring.

My Mel double crossover works perfectly without gaps on DC or DCC. The Atlas Custom Line #6 frogs don’t need to be powered for my locomotives, my shortest locomotive is a MDC 0-6-0 and they work great going through all my Atlas non powered frogs.
 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

 

 

 

 

Do the Atlas crossing or the switches have non-conducting sections, such as insulated frogs?

Thanks,
Bruce

 

The short answer - YES.

I'm in HO, never messed with N, but most comercial track today has isolated frogs and feed thru wiring that prevents shorts.

I hand layed track for years in HO, now I prefer commercial turnouts because of the wiring. Again, i have no N scale experiance, but I would skip the FastTracks if I were you.

Pretty sure Atlas N gauge track works just like their HO track, So it would be just like Mel's info on his site.

Sheldon

    

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Posted by RR_Mel on Wednesday, November 25, 2020 8:12 AM

In case your kicking around building your own double crossover ....

I did a quickie CAD drawing using pictures from the Atlas web site using Atlas code 55 #7 turnouts with a 11¼° crossover and came up with 1.8857” center to center and 16.4912” total length.



Could be shrunk down with some chopping to 1.3625” center to center by 13.994” total length.

The stock Atlas turnouts and crossover will work without any special gaping or wiring providing you don’t plan on using a different power source for the dual mainline.

Mel



 
My Model Railroad   
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Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

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Posted by RR_Mel on Wednesday, November 25, 2020 9:00 AM

Lastspikemike

 

So my crossing shorting risk will disappear once I power all rails from one DCC booster.

 

Yes
 

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

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Posted by Neptune48 on Wednesday, November 25, 2020 10:37 AM

Lastspikemike

Looking at the track plan I'd be tempted to ditch the compacted crossovers in favour of moving the turnouts further apart and creating passing tracks instead, albeit short ones. Using curved turnouts or opposite hand straight turnouts with the diverging track as the mainline can get you the room you need.

It may add to the switching complexity as an added bonus.  

 

 

Brilliant!

All this time I had just accepted there was insufficient room and that a double crossover was necessary, but you were absolutely right, Lastspikemike!  I bow in the presence of greater intelligence!

Revised Track Plan

Of course I'll have to adjust some of the block lengths and rework the control panel, but this takes a huge load off my mind.

The KISS principle reigns supreme!

Thanks,
Bruce

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Posted by Neptune48 on Wednesday, November 25, 2020 10:41 AM

Lastspikemike

Put another way, as long as the entire crossover including four turnouts and the crossing have isolated frogs (or polarity reversing frogs) and never get power from more than one power source (only the one polarity) no special wiring should be required. 

Is that the situation?

So my crossing shorting risk will disappear once I power all rails from one DCC booster.

 

It's a moot point now, but getting the power to the frogs and the diamonds without a plethora of switch gangs or relays was my issue.  But your solution (my reply above) solves everything.  Thanks again!

Regards,
Bruce

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Posted by Neptune48 on Wednesday, November 25, 2020 10:44 AM

RR_Mel

In case your kicking around building your own double crossover ....

I did a quickie CAD drawing using pictures from the Atlas web site using Atlas code 55 #7 turnouts with a 11¼° crossover and came up with 1.8857” center to center and 16.4912” total length.



Could be shrunk down with some chopping to 1.3625” center to center by 13.994” total length.

The stock Atlas turnouts and crossover will work without any special gaping or wiring providing you don’t plan on using a different power source for the dual mainline.

Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.

Thanks for the help, Mel.  As you have probably seen above, Lastspikemike suggested an alternative that solves the issue with a lot less fuss than my being locked into thinking a double crossover was even necessary.

Everyone on this thread has been very helpful, and I thank you all.

Regards,
Bruce

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Posted by ATLANTIC CENTRAL on Wednesday, November 25, 2020 10:58 AM

You are welcome, and I was about to suggest the same thing Mike suggested. The real railroads avoided double crossovers. Modelers should use them sparingly only when spacs and function really require them.

Sheldon

    

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Posted by RR_Mel on Wednesday, November 25, 2020 11:46 AM

ATLANTIC CENTRAL

The real railroads avoided double crossovers. Modelers should use them sparingly only when spacs and function really require them.

Sheldon

 

Have to agree with you Sheldon.  

I was fascinated with double crossovers and double slip as a teen and never got over it.  I finally decided to include either a double slip or double crossover in my final layout design just because I wanted one.

I couldn’t find a manufactured code 83 double crossover that would pass my fleet of large flange Rivarossi Cab Forwards without the wheels shorting so I ended up with a single crossover using a pair of Atlas #6 turnouts.  Running SP Cab Forwards was more important to me than the double crossover.

After about 20 years of frustration not having a double crossover I decided it was time to do something about it.  All my large flange Rivarossis would clear all my code 83 #4 & #6 Atlas Custom Line turnouts without problems so I decided to build my own double crossover using Atlas turnouts.  And it worked first try and has never had a single problem since it was installed in 2012.  I didn’t have any problems with the #6 turnouts on my layout but I included the frog wires to all four turnouts.  Every locomotive ran without problems so I never used frog power.  I have one 0-4-0 switcher with a slope back tender and it doesn’t have problems with unpowered Atlas frogs.
 


The angle of the dangle is pretty good too, no problems with the ‘S’ curve even at full speed (about 70MPH scale).

Mel



 
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I'm beginning to realize that aging is not for wimps.

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Posted by RR_Mel on Wednesday, November 25, 2020 2:43 PM

This is my HO twice-around layout.



The red track climbs from 0 to 10” then back down to 0 through the helix.  A single mainline folded on top of its self with my double crossover connecting the tracks.

All of my layouts have been of twice-around design modeled after my mentor John Allen’s original Gorre & Daphetid layout.  My second layout was a 4’ x 8’ duplicate of John’s original 3’7” x 6’8” layout.

I made a wye out of the loop so I could reverse directions.

 

Mel



 
My Model Railroad   
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I'm beginning to realize that aging is not for wimps.

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Posted by rrinker on Wednesday, November 25, 2020 8:11 PM

 Keep it simple - there is no need to switch cabs int he middle of the crossover. Either the whole thing should connect to one cab, or the whole thing should connect to the other cab. Two trains can't run through there at the same time anyway.

 Since two traisn cab go straight at the same time, then the top two turnouts and the bottom two turnouts can be different blocks, same as any other block on the layout. But the diamond int he middle - that should only connect to one cab or the other, notroute back and forth, ro have one angle be be cab 1 and the other angle be cab 2. You could use the second set of contacts on one Tortoise to feed the diamond from whichever cab is feeding the lead in block. You need two sets, so use the two diagnonal toroises, since for the train to get rhrough, the block it is entering from and the block is it leaving from have to sbe set to the same cab.

 An insulated frog diamond is your friend here, like an Atlas one. AN all rail sort like a Fast Tracks one requires far too much switching - or is easily wired with Frog Juicers, but they only work with DCC. It actually shouldn;t be too bad - since only oen train can cross the diamond at a time, if all 4 legs are insulated, the whole thing can be powered by the contacts of the top eft and lower right Tortoise, OR the lower left and top right. Frog power for the turnouts is straightforward, same as any other turnout. Since only one train can occupy the duiamond at a time, if crossing from top left to bottom right, those two sets of contacts would power the entire thing when those two turnouts are set to diverging. The bottom left and upper right would ahve to be set straight. When all 4 are set straight,t he diamond has no power. And then the lower left and top right power the diamond when they are both set to diverging. Forget to set one to diveging - train dies on the diamond because it's not fully powered. Set all 4 to diverging, it will cause a short, because this is an invalid configuration. A rotary switch makes a good control here, you need 3 options: upper left and lower right diverging, others straight, all straight, and lower left and upper right diverging, others straight. That just needs a 2 pole, 3 position rotary switch, no need for 8 decks or any crazy combo like that. You do want a non-shorting roatry switch. All 4 Tortoises would connect to each of the 3 positions, just with different polaritys so they move the right way at each step. IE, if the first position needs Tortoise #1 to be normal, then that may mean pin 1 got to pole 1 on the rotary, and pin 8 goes to pole 2. If the second position requires Tortoise 1 to reverse, then it would have a second connecttion with pin 8 on pole 1 and pin 1 on pole 2. If the third position requires it to be normal again, the it would be connected to the third position with pin 1 on pole 1, and pin 8 on pole 2. Some diodes will take care of conflicts, sort of like a diode matrix type of control.

                                            --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by Neptune48 on Thursday, November 26, 2020 12:42 AM

Lastspikemike

 

Well, love to take credit but there's a lot of brainpower and even more expertise available on this forum. I dig around and maybe put stuff together in one post but it's pretty much all from somewhere else on this forum or in one or more of the excellent books on model railroading.

One other thought you might like to consider if you can fit the required grades in is the well known and popular "twice around". This is a pleasant variation on your inside and outside loop. Come to think of it you can also achieve this with one of your crossings if you don't mind dealing with the risk of collision. 

You connect your inside loop to your outside loop instead of keeping them separated. You make a folded figure 8 with either a bridge/tunnel and grade separations or one diamond crossing if the necessary grades won't fit or you prefer no grades.

The place to cross over with a tunnel or bridge would be in one of the double curves on your plan. The crossover would work best in one of the straight sections.

 

If I remember correctly, I wasn't able to do bridges or tunnels as the grades would have been too steep.  The only changes in elevation are the mainlines and their sidings will be higher than the yard and industrial tracks, with ramps in the sub-roadbeds to make the transitions.

I think this layout might also see duty as a "Christmas pike" with two trains running continuously in opposite directions just to amuse and delight civilians.

Regards,

Bruce

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Posted by Neptune48 on Thursday, November 26, 2020 12:45 AM

rrinker

 Keep it simple - there is no need to switch cabs int he middle of the crossover. Either the whole thing should connect to one cab, or the whole thing should connect to the other cab. Two trains can't run through there at the same time anyway.

 Since two traisn cab go straight at the same time, then the top two turnouts and the bottom two turnouts can be different blocks, same as any other block on the layout. But the diamond int he middle - that should only connect to one cab or the other, notroute back and forth, ro have one angle be be cab 1 and the other angle be cab 2. You could use the second set of contacts on one Tortoise to feed the diamond from whichever cab is feeding the lead in block. You need two sets, so use the two diagnonal toroises, since for the train to get rhrough, the block it is entering from and the block is it leaving from have to sbe set to the same cab.

 An insulated frog diamond is your friend here, like an Atlas one. AN all rail sort like a Fast Tracks one requires far too much switching - or is easily wired with Frog Juicers, but they only work with DCC. It actually shouldn;t be too bad - since only oen train can cross the diamond at a time, if all 4 legs are insulated, the whole thing can be powered by the contacts of the top eft and lower right Tortoise, OR the lower left and top right. Frog power for the turnouts is straightforward, same as any other turnout. Since only one train can occupy the duiamond at a time, if crossing from top left to bottom right, those two sets of contacts would power the entire thing when those two turnouts are set to diverging. The bottom left and upper right would ahve to be set straight. When all 4 are set straight,t he diamond has no power. And then the lower left and top right power the diamond when they are both set to diverging. Forget to set one to diveging - train dies on the diamond because it's not fully powered. Set all 4 to diverging, it will cause a short, because this is an invalid configuration. A rotary switch makes a good control here, you need 3 options: upper left and lower right diverging, others straight, all straight, and lower left and upper right diverging, others straight. That just needs a 2 pole, 3 position rotary switch, no need for 8 decks or any crazy combo like that. You do want a non-shorting roatry switch. All 4 Tortoises would connect to each of the 3 positions, just with different polaritys so they move the right way at each step. IE, if the first position needs Tortoise #1 to be normal, then that may mean pin 1 got to pole 1 on the rotary, and pin 8 goes to pole 2. If the second position requires Tortoise 1 to reverse, then it would have a second connecttion with pin 8 on pole 1 and pin 1 on pole 2. If the third position requires it to be normal again, the it would be connected to the third position with pin 1 on pole 1, and pin 8 on pole 2. Some diodes will take care of conflicts, sort of like a diode matrix type of control.

                                            --Randy

 

 

Thanks, Randy.  I think this might have solved my issue, but I learned the doulbe crossovers were not necessary after all.  Fortunately I hadn't bought the rotary switches yet, and all I need to do is add a few more DPDT toggle switches instead.

Thanks,
Bruce

  • Member since
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  • From: Maryland
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Posted by ATLANTIC CENTRAL on Thursday, November 26, 2020 9:49 AM

The biggest irony of the double crossover is that you don't really want any curves starting right at the switch points, so by the time you leave some straight track on either side, you could have just used two opposite crossovers.

Now if you you really want to see a wild double crossover, go visit the Severna Park Model Railroad Club.

They have a double crossover - BUT - one of the turnouts is a double slip switch, so three tracks on one side, two tracks on the other side, every route possible, in less than two feet. And the turnout next to the double slip is the opposite hand, so it changes the direction of the mainline, using the curved route as the main.

The third track is the yard lead off the double track mainline. The whole thing is scratch built and now about 55 years old. It worked flawlessly for the many years I was a member there. Here is a link to a photo:

https://scontent-iad3-1.xx.fbcdn.net/v/t31.0-8/10258017_772636129433741_8679008871970326046_o.jpg?_nc_cat=103&ccb=2&_nc_sid=cdbe9c&_nc_ohc=zujNGJ_4IUUAX-uVeQM&_nc_ht=scontent-iad3-1.xx&oh=4507f8017cfe2e9c38355fc7e4e2859c&oe=5FE71D6E

Sheldon

 

    

  • Member since
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  • From: Bakersfield, CA 93308
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Posted by RR_Mel on Thursday, November 26, 2020 10:08 AM

Now that is slick Sheldon!!!  I could have built my layout with that design and would have had a double slip too.  Didn’t think that way back in 1988 during the design or my layout would have had a double slip.


Mel



 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Thursday, November 26, 2020 10:25 AM

 Friend of mine had something like that on his N scale layout. Only kicker is, it was hand laid with Code 40 to fine scale standards. Physically it was very reliable, vbut even I gave up trying to figure out a combination of Tortoise contacts to set all the frogs correctly. Eventually he discovered that one of the routes he thought he needed was never in fact actually used so he simplified it by making it a single slip and a double crossover. Frog Juicers weren't around yet, but that would have been the way to go with this thing.

 His new layout has nothing more complex than a double crossover. Still handlaid, Still Code 40, still fine scale standard. Locos are no problem, he scratchbuilds those, and lathe turns wheelsets for the rolling stock from standard N scale metal wheelsets.

                                      --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    September 2004
  • From: Dearborn Station
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Posted by richhotrain on Thursday, November 26, 2020 10:34 AM

ATLANTIC CENTRAL

Now if you you really want to see a wild double crossover, go visit the Severna Park Model Railroad Club.

They have a double crossover - BUT - one of the turnouts is a double slip switch, so three tracks on one side, two tracks on the other side, every route possible, in less than two feet. 

And, once again, a track configuration that can be found on the prototype. At one time, Dearborn Station in downtown Chicago had a double crossover with double slips on two diagonal ends of the double crossover. Gotta love that stuff.

Rich

Alton Junction

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  • From: Southern Florida Gulf Coast
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Posted by SeeYou190 on Friday, November 27, 2020 10:22 AM

Neptune48
Fortunately I hadn't bought the rotary switches yet, and all I need to do is add a few more DPDT toggle switches instead.

Bruce, if there is any chance you will decide to use a double crossover, and will need the rotary switch, you might want to order it now just to have it.

I needed a 12 pole double throw rotary switch to control a double crossing with solid frogs and signalling. I ended up ordering a military surplus switch from a former Soviet block country!

It is better to have it and not need it.

-Kevin

Living the dream.

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