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Designing wyes for turning engines

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Posted by back_pack on Monday, April 30, 2007 12:41 PM

I am working on a similar problem in designing my own layout. I am also going to be using Bachmann 2-8-0s... I had not found any information on the minimum radius that the loco would handle, so I contacted Bachmann. They recommend 18" as the minimum radius, and that seems to jive with my experiences with these models and Peco small-radius curved turnouts. The 2-8-0 usually derailed going into the diverging route of those turnouts.

Andy

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Posted by Midnight Railroader on Monday, April 30, 2007 10:23 AM
 IRONROOSTER wrote:

There is nothing wrong with having multiple minimum radii on a layout.

By definition, the "minimum" of anything is the smallest.

So, if you have a 12" anywhere curve on your layout, 12" is your minimum radius; any larger curve is NOT the smallest one. You might want to say you have a "minimum mainline radius," if that clarifies things.

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Posted by John Busby on Monday, April 30, 2007 5:43 AM

Hi NevinW

No one seems to have stated the obviouse.

That in a lot of cases the loco depot is inside the triangle so all your loco sheds coal stage and water tower will be inside.

I have also seen a case where a cattle yard is on the top tail of the triangle

It has been stated that they take a lot of room this is unfortunatly unavoidable, but I would forget the drop flap idea that adds more electrical problems to what you already have by choosing a turning triangle instead of a turntable IE stoping a loco plunging into the void when the flap is down

regards John

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Posted by pcarrell on Sunday, April 29, 2007 10:26 AM

 R. T. POTEET wrote:
 pcarrell wrote:
I'm probably going to get slapped around for saying this, but I love N scale!


Philip, will you please stop trying to bring shame and remorse to all of our HO Scale friends out there; most of them are just beginning to realize that HO doesn't stand for Half-Oh but Horribly Outclassed.  Actually, I have always felt that HO should change its name to HA - Half Acre which is about how much room it takes to get a decent looking layout.

WOW!

R.T., you're on your own now buddy! 

I may agree, but I'm not going to say it out loud!

Philip
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Posted by Hudson on Sunday, April 29, 2007 12:53 AM
Silly.
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Posted by Anonymous on Sunday, April 29, 2007 12:13 AM
Slightly off topic, Im sticking with HO scale because N scale are no good with the sound units. When I decline in eyesight I will be going to O scale.
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Posted by R. T. POTEET on Sunday, April 29, 2007 12:02 AM
 pcarrell wrote:
I'm probably going to get slapped around for saying this, but I love N scale!


Philip, will you please stop trying to bring shame and remorse to all of our HO Scale friends out there; most of them are just beginning to realize that HO doesn't stand for Half-Oh but Horribly Outclassed.  Actually, I have always felt that HO should change its name to HA - Half Acre which is about how much room it takes to get a decent looking layout.

From the far, far reaches of the wild, wild west I am: rtpoteet

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Posted by R. T. POTEET on Saturday, April 28, 2007 11:53 PM
 pcarrell wrote:

Have you thought about a scissors wye?  It can work in tight places and keep your minimum radius reasonable.  You could even scissor more then one side.  And yes, there is a prototype.  It was used at least once on a ledge in the Rocky Mountains, but I can't remember where.  Can anyone help with that?



Chuck Yungkurth had a scissors wye on at least one of his many Bellefonte and Snowshoe layouts; the one that I encountered was written up in MR in the mid-'60s.  HIs was a simple scissors; somewhere since then I ran into a layout that had a double scissors; you are right about one thing - it does save one heckuvalottaroom.

From the far, far reaches of the wild, wild west I am: rtpoteet

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Posted by cowman on Thursday, April 26, 2007 5:13 PM

An old Atlas Custom-Line layout book I have shows a wye: 3 wye switches, 3-18" radius curves and 3-1/3 18" radius curves, doesn't take up much room.  New books probably have the same diagrams, plus it shows many other wyes.  I used the small one on a layout years ago and it worked fine for some medium length 4 axle diesels.

Good luck,

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Posted by pcarrell on Wednesday, April 25, 2007 8:42 PM
I was just refering to how much easier it is to fit stuff sometimes in N.
Philip
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Posted by Texas Zepher on Wednesday, April 25, 2007 7:14 PM
 pcarrell wrote:
I'm probably going to get slapped around for saying this, but I love N scale!
I did N-scale for about 20 years.  At one time I had every brass N-scale locomotive ever built.  As my modeling interests and desires changed, I switched back to HO.
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Posted by Anonymous on Wednesday, April 25, 2007 7:03 PM

Im thinking something that might be not possible.

Take the atlas switching layout here before us in this thread with the wye going into a corner.

How about we flip that wye and come out into the operator's area between the two sides of the layout instead. Potentially more room for a bigger wye and possibly one extra industry or something back there.

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Posted by pcarrell on Wednesday, April 25, 2007 6:31 PM
I'm probably going to get slapped around for saying this, but I love N scale!
Philip
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Posted by conagher on Wednesday, April 25, 2007 6:07 PM
Hey Texas Zephyr...that's a nice-looking switching layout that appears to be a lot of fun
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Posted by Texas Zepher on Wednesday, April 25, 2007 4:36 PM

 NevinW wrote:
Unlike my prototypes who had endless desert I have only a 2 foot wide shelf.....I am also thinking about extending the wye out into the room beyond the shelf edge but using some kind of system to drop the tail of the wye down out of the way when the layout is not in use.
Any chance the 2 foot wide shelf goes around a corner making an "L" shape?  If so the tail of the wye can be shoved into the corner.

If not, the extension will not have to be very long.   I've got a wye with 22" radius in the corner.  It only needs about 3.5' to work.  An 18" needs even less.  See the far end of the picture below.  The GN box car is on the closest turnout of the wye.  The tail is next to the chimney.

as usual click the image to enlarge

There is an 18" radius wye in the plan on the Atlas plan here: http://www.atlasrr.com/Code100web/images/10019.jpg

 

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Posted by NevinW on Wednesday, April 25, 2007 4:35 PM
Using 18" radius curves, a <1 foot long tail and atlas #4 turnouts I was able to fit wyes into the corners where the shelf makes a 90 degree turn.  It is a tight fit but might work.  As soon as I get a chance, I'll post a copy of the design.  -  Nevin
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Posted by Dave-the-Train on Wednesday, April 25, 2007 2:27 PM

One thing you might look at is using a sector plate "off scene" in place of a large chunk of the wye and the tail track.

A sector plate is similar to a turntable but the pivot is at one end not in the middle.

If the Main track side of the wye runs round a curve in a corner the two legs of the wye head into the corner and vanish between buildings/under bridges.  then behind the scenery you put the sector plate with the pivot way back in the corner. 

To use you set the plate to the track you are coming from, run the loco on, swing the plate to the other track and send the loco off down the other leg of the wye.

If you want to get really complicated you can combine the features of a sector plate with those of a transfer table Mischief [:-,]

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Posted by IRONROOSTER on Wednesday, April 25, 2007 9:41 AM

There is nothing wrong with having multiple minimum radii on a layout. John Armstrong in his book "Track Planning for Realistic Operation" recommends you have multiple minimums for different situations.

While many HO locomotives are made to go around 18" radius, you'll need to experiment for 15".  Since Atlas makes 15" radius track, I suggest you buy a pack and test your locomotives.

One thing you can do in a corner is add a triangular section (with a curved hypotenuse) to the shelves at the corner - this will enable a wye tail into the corner to be a little longer using 3 wye turnouts.

Good luck

Paul 

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Posted by SpaceMouse on Wednesday, April 25, 2007 9:29 AM

I was recently at an NMRA regional event where a man had a modular layout with a lot of switching. However to make the layout work on it's own, as it was at the event, he needed a 2 foot extension on the main--on both sides. He had the extension clamp on and it plugged in as any other module would attach. It was a lightweight 3" channel with a diagonal support. That's it.

There's no reason why you couldn't do something similar to extend your wye.

 

Chip

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Posted by fwright on Wednesday, April 25, 2007 9:08 AM

I am going to disagree with the other posters to some extent.

First of all, I would be very cautious about using any curve radius below 18".  Test first!

Using a pure 18" radius (including turnouts) you can squeeze an 18" radius wye in the corner of 2ft deep shelves.  The tail track has to be oriented at a 45 degree angle into the corner, and will have a maximum 10" clearance.  Measure the length of your locomotives first!  And there will be no room for a curved backdrop.

If you can add just a little corner fill on the aisle side of the shelves, you can get a longer tail track.  Using the Atlas Custom-Line or other commercial wye turnouts will cost you a little tail track length.  The same for anything but 18" radius Snap Switches at the base of the wye.

Worth plotting out in XTrkCad with your selected turnouts to see how it will all fit.

my thoughts, your choices

Fred W

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Posted by tomikawaTT on Wednesday, April 25, 2007 1:40 AM

No matter how you look at it, a wye with a tail track long enough to turn a 2-8-0 is going to take as much space as a 'balloon' reversing loop - and I would not suggest either a drop down (I have one - major PITA, but I'm stuck with it) or reducing your minimum radius.

Why not set two turnouts where they would have to be if the wye was going to go through the backdrop, then have the tracks disappear behind something big and opaque.  Only you will know that there's actually an Atlas turntable back there.

Chuck (modeling Central Japan in September, 1964)

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Posted by conagher on Tuesday, April 24, 2007 9:29 PM

I know this will not be applicable to Nevin's smaller steamers but for anyone else considering a Wye using the older '40s-'50-'60s locos, here's what our club did:

Rather than take space with everything required for a Wye that could otherwise be used for scenery or buildings, we merely ran the loco behind a tall hill (or building) and reversed it with an 0-5-0 switcher.....an operator's hand. It may not be prototypical but it served our purpose well for years.

After a while, we began using an F3A-F3A set for switching and eliminated the need to do any turning. Eventually we settled for GP7s & 9s erasing all directional concerns.

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Posted by Anonymous on Tuesday, April 24, 2007 8:16 PM
Dont go down below your minimum radius. Consider a turntable instead.
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Posted by pcarrell on Tuesday, April 24, 2007 7:29 PM

Have you thought about a scissors wye?  It can work in tight places and keep your minimum radius reasonable.  You could even scissor more then one side.  And yes, there is a prototype.  It was used at least once on a ledge in the Rocky Mountains, but I can't remember where.  Can anyone help with that?

Philip
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Posted by nbrodar on Tuesday, April 24, 2007 6:43 PM

There are a couple ways to handle it.  You really don't want to drop below your min radius.

One the solution you have already, using a drop down tail track.

The other is to put the wye in a corner where the benchwork is deeper.  Have the front of the wye curve around the corner, and point the tail track back into the corner.

Nick

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Designing wyes for turning engines
Posted by NevinW on Tuesday, April 24, 2007 6:30 PM

Most of the railroads I am interested in modeling used wyes instead of turntables to turn their engines.  Unlike my prototypes who had endless desert I have only a 2 foot wide shelf.  Wyes take up considerable space, especially if you stick to a minimum radius.  Since I am going to be using small engines like 4-6-0 and 2-8-0 (Spectrum) in HO scale I an thinking about going way below my usual minimum radius down to a 14-15 inch radius.  My standard min. radius is 24" as I want to run the old MDC Pullman Palace cars.  Will small engines go around a 15" radius without any cars attached or is this a bad idea and likely to cause problems?

I am also thinking about extending the wye out into the room beyond the shelf edge but using some kind of system to drop the tail of the wye down out of the way when the layout is not in use.  Has anyone build such a device?  How did  you do it?  thanks -  Nevin

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