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Hidden crossover track

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  • Member since
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Hidden crossover track
Posted by MarkZitz on Sunday, December 9, 2012 8:35 PM

I am building a layout that has a crossover that will be hidden after the scenery is done.  it will be under a mountain.  I realized yesterday while running trains that there could be a problem.  There could be a crash if not paying attention.  The train will disapear for a while before getting to the crossover so, it might be easy to forget about it while doing other things. 

Is there a device that would shut down one train if there was another on in the crossing?

I use DCC.  I would assume that there is a componant that would handle this but, not sure what to use.

Thanks,

Mark

 

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Posted by jrbernier on Sunday, December 9, 2012 9:27 PM

  Are you talking about a 'cross-over' - two parallel tracks wqith two switches, or a 'crossing' - two tracks crossing one another at an angle?

Jim

Modeling BNSF  and Milwaukee Road in SW Wisconsin

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Posted by Phoebe Vet on Sunday, December 9, 2012 9:35 PM

Please clarify.  Are you talking about a crossover, a pair of switches that allow a train to move from one track to another, or a crossing where one track crosses another track?

Dave

Lackawanna Route of the Phoebe Snow

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Posted by MarkZitz on Sunday, December 9, 2012 9:37 PM
Sorry about that. It is a crossing. Two tracks that tross each other at a 45 degree angle.
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Posted by Phoebe Vet on Sunday, December 9, 2012 9:47 PM

The simplest way would be to isolate the crossing and the approach track then power them through a DPDT switch so that only one approach is powered at a time.  You can also use occupancy detection to cut the power to the other approach when one is occupied.

Dave

Lackawanna Route of the Phoebe Snow

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Posted by hobo9941 on Sunday, December 9, 2012 11:14 PM

If anything is going to happen, it will happen where you can't see it or reach it. Wink

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Posted by richhotrain on Monday, December 10, 2012 4:37 AM

In other words, don't do it.

Can you elevate the crossing so the trains never meet?

Rich

Alton Junction

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Posted by MisterBeasley on Monday, December 10, 2012 6:41 AM

I'd suggest building the scenery so that you have access.  Consider either an opening beneath the layout that you can reach your hand  through or a section of scenery that lifts off.

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

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Posted by BroadwayLion on Monday, December 10, 2012 7:05 AM

Yeah, this is why railroads have interlocking plants. For this junction, only one switch is necessary: It controls the signals and the power. You clear the east-west route, or your clear the north-south route. The unclear route is turned off and its signals are red. Use a three position switch so that it is RED in all directions until you clear it for a train.

Well, that is how a railroad would do it, but how does it work on a layout? This depends on how big the layout is and how many trains you have running.

Out in the sticks the main-line (or the superior railroad) keeps the lights aligned for its route, and when an inferior train approaches, it must stop, and if the way is clear and/or has permission from control, reverses the signals to give his train the right of way. Once clear, the brakeman must realign the route to the normal position.

In other words it is treated just like any other turnout.

ROAR

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

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Posted by MarkZitz on Monday, December 10, 2012 8:30 PM

There will be access to it.  This is a modular layout. I doubled the length of the mainline by using the crossing.  Now the mainline makes a lap around the layout and then it makes another lap that is mostly hidden either behind backdrop or under mountain areas.  So, in the center of the layout, behind the backdrops, there will be access to all of the hidden areas.  What concerns me is that when a train disapears, i could be distracted by something else and there could be a crash.  I was just looking for an electronic solution.

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Posted by fwright on Tuesday, December 11, 2012 12:22 PM

MarkZitz

....I doubled the length of the mainline by using the crossing....What concerns me is that when a train disapears, i could be distracted by something else and there could be a crash.  I was just looking for an electronic solution.

The basic idea of interlocking works regardless of DCC or DC.  The crossing itself is electrically isolated as 2 sections of track - one for each path.  The approaches to each crossing path are also electrically isolated.  A detection circuit (electronic or optical) detects the presence of a train on one of the 2 crossing paths.  The presence of a train on the crossing triggers a relay (or electronic switch) to shut down both the approaches for the opposite crossing path.

This is fairly simple interlocking, and can be implemented with relays, electronic switches, or digital logic with drivers to the approaches.  Relays are perhaps the simplest conceptually for a small logic tree like this one.  The relays would be driven by the detection circuits.

The biggest obstacles to be overcome would be:

  • reliability of detection with all train lengths used
  • ensuring approach blocks work consistently with all trains
  • Sudden stopping and starting of trains - you would not be issuing a DCC "train stop", but cutting power.  Having a DCC "train stop" issued in the approach blocks would add another level of complexity.

my thoughts, your choices

Fred W

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Posted by Phoebe Vet on Tuesday, December 11, 2012 1:57 PM

That certainly would work, but the DPDT switch ,so that only one approach at a time can be powered, accomplishes the same thing for just a couple of dollars.  Of course you will have to pay attention and throw the switch by hand.

Dave

Lackawanna Route of the Phoebe Snow

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