Newly Retired and want to do it right - DCC Wye or turntable on end of reverse loop

[richhotrain]

BARRY HESPENHIDE

I am going to build my dream layout.  I have Atlas Layout plans for HO-29 The Central Midland.  In the lower right hand corner is a spur that is the tail of a reverse loop.  I would like to put a Wye or turntable in that area..  How would I wire it for DCC?  Thank you Barry Hespenhide

 

If you treat the entire yard, as well as those spurs in the lower right circle of track, as a single reversing section, as shown in that Atlas forum link, then replacing the two spurs with a turntable would require no special wiring.

In addition, no auto-reverser would be required for the turntable since most modern turntables, like Walthers, build in devices to automatically match polarities as the turntable rotates.

One auto-reverser and four sets of gaps are all that are needed.

Rich

[BARRY HESPENHIDE]

BARRY HESPENHIDE

I am going to build my dream layout.  I have Atlas Layout plans for HO-29 The Central Midland.  In the lower right hand corner is a spur that is the tail of a reverse loop.  I would like to put a Wye or turntable in that area..  How would I wire it for DCC?  Thank you Barry Hespenhide

Thank you all for your input will take all ideas into consideration. Barry

[carl425]

 

Layout design has evolved substantially in the 50+ years since the old Central Midland was published.  I would encourage you to shop around a little before committing to that plan.  When you figure in the access that is required on all sides of that plan, you can do something much more interesting in the same space.

 

I had a neighbor down the street in the late 60's that built that plan.  The Granite Gorge & Northern which was the preceding plan in the same book was up the street.

 

[jrbernier]

Barry,

  You do NOT have a reverse loop(electrically speaking).  You do have a double track wye that wiil need insulators on all four leads where they connect to the main line.  The auto reverse unit will power the entire wye area, including that switchback area you are concerned about.

  If you put a turntable in that area, you have a couple of options:

* - Most newer turntables(like the Atlas, & Walthers Cornerstone series) have 'auto reverse' built in.  Just follow the installation instructions about placement of the main lead track.

* - Some older turntables(like the old Walthers/Heljan) will need a seperate 'auto reverse' unit, or at least a DPDT switch to control the polarity.

Jim

[MisterBeasley]

This is a point of semantics, but it's better to use the commonly-accepted terminology.  As drawn, that layout does not have a "reverse loop."  A reverse loop is typically a teardrop-shaped loop of track that you enter and leave at the same point, but going in the opposite direction.  This layout sort of does that, but the "reversing section" is actually the yard tracks center-left, and that's how I would wire it.

Then, I have to ask why you would want a reversing wye at that point of the layout.  You need to go through the double-wye anyway just to get to it.  A turntable or roundhouse, on the other hand, is just a neat thing to have.  The Atlas turntable does take care of polarity reversal, by the way.

This is my own turntable and roundhouse, seen from directly above:

It's based on an Atlas turntable that I "pit-bashed" by dropping the turntable itself below the surface and adding a bridge, connecting them only at the pivot point.  Overall dimensions are about 24 inches by 16 inches.  The engines in the picture are GP9s.  Even this very small turntable and roundhouse takes up a lot of space, and it can't turn or house anything longer than a 9-inch engine.

[rrinker]

 That area I think is set up as an industrial area, like a downtown switching district handled by a turn out of the yard, that yard being the part ont eh left that is at a different level than the loop. That whole yard is already part of a double-track wye arrangement. While the part you're talking about could eb turned into the service area, it would probably be more logically located on the left off the yard.

 If you use something larger than the Atlas turntable, like the Walthers one, they use split rail pickup so no other reversing is necessary. Reversers are necessary for the sueprimposed wyes at the right center.

                  --Randy

[BARRY HESPENHIDE]

the lower section of the reverse loop, with the track inner circle spur (like a industal area short tracks) or a turn table?

 or wye?

[BARRY HESPENHIDE]

the section of track that is contained in the lower circle section. It looks like a parking area. 2 spurs with three turn offs. I am wanting to modify this section of track. I have DCC and have 2 stationary reverse decoders. I recently moved and had a set up before but now have more space to enlarge :) . My system is NCE DCC. Thank you Barry

[richhotrain]

Here is a good discussion of the reversing sections from the Atlas forum.

http://forum.atlasrr.com/forum/topic.asp?ARCHIVE=true&TOPIC_ID=54511

Rich

[MisterBeasley]

Welcome aboard! 

I, too, am about to retire.  46 calendar days, but only 13 work days and, best of all, only 4 more Mondays.

That layout as posted by Rich has a complicated double wye in the center.  But, DCC autoreversers can handle it.  You can use the plan in the diagram to reverse short trains.

A turntable will only reverse a locomotive or perhaps a single passenger car.  On the other hand, a turntable is an interesting piece of scenery for the Transition Era and before.  If you can work it in with a roundhouse, so much the better.  I run my turntable the old fashioned way, with a simple double-pole, double-throw (DPDT) toggle switch, but if you'd like, you can put a DCC decoder on it and run it from your throttle.  Most of the turntable models today are already set up to deal with track polarity automatically, and those that are not can be easily wired up to one of those autoreversers.

I've got two of the older model PS-REV autoreversers from Tony's Trains / DCC Specialties.  After 10 years or so on the job, they still work perfectly.

[richhotrain]

Here is the plan for the Central Midland.  Can you show us the area that you are referring to?  Specifically, where the spur that is the tail of a reverse loop?

Rich

[gmpullman]

Hi, Barry and Welcome AND congratulations on your recent retirement! I have 644 days to go, but who's counting!

There are a few options out there for making the rails in DCC automatically switch "polarity" at a reversing section. I have experience with only two and those are the DCC specialties PSX AR which I have to admit is a bit pricey at $54. but they have worked flawlessly for me since I installed them about ten years ago (I have three on my layout.) 

http://www.tonystrains.com/technews/powershield_x.htm

The other is a Digitrax AR-1 that, by my estimation is a bit less sophisticated, using manual instead of solid state relays but it gets the job done for about 50% the cost.

http://www.digitrax.com/products/autoreversing/ar1/

Here's a summary that I stumbled across that may help you decide:

http://www.litchfieldstation.com/xcart/home.php?cat=55

If you Google DCC auto reversing you will find quite a bit of information there. I don't have that Atlas track diagram handy but I have learned that you neet to have the train or engine length shorter than your reversing section and you need to have both rails gapped or insulated joiners installed at the entrance/exit of the reversing section. I was pulling a long string of passenger cars through the reverse section and was reminded right away that the train was too long to fit! Freight cars with completely insulated wheels are a different story but there can be enough of a "bridge" at the gap to confuse the reverser and it will think there is a real short.

I did my turntable a little differently than most. I made a cam that is on the shaft under the layout. A Microswitch rides on this cam and when the bridge is between tracks roughly 180° apart the Microswitch changes a DPDT relay that reverses the rails on the turntable bridge.

Its a little fuzzy in this shot but maybe you get the idea. If you're using an Atlas turntable you might be able to get away with just using a DPDT switch that you manually throw. I'm pretty sure the Atlas turntable just has two screw terminals that feed the rails so you could rig up an LED to let you know if the rails are electrically "in phase" or need to be switched.

I'm sure others will have some input here as well. You have lots of options, this is just my experience...

Again, 

Ed

 

[BARRY HESPENHIDE]

I am going to build my dream layout.  I have Atlas Layout plans for HO-29 The Central Midland.  In the lower right hand corner is a spur that is the tail of a reverse loop.  I would like to put a Wye or turntable in that area..  How would I wire it for DCC?  Thank you Barry Hespenhide