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Distance from Turntable to Roundhouse, Walthers

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Posted by BATMAN on Thursday, July 22, 2021 4:37 PM

Billwiz

 

 

 

 

 

 

 

 

 
 

Yes

BATTRAIN is what my youtube page is called. Nothing on it currently though.

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 


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Posted by Billwiz on Thursday, July 22, 2021 11:28 AM

 

BATMAN

 

 
snjroy

I'm still waiting to see the Batcave on that layout Smile

Simon

 

 

 

Now that's a cool idea!Laugh

 

 

 

 

 
snjroy

I'm still waiting to see the Batcave on that layout Smile

Simon

 

 

 

Now that's a cool idea!Laugh

 

[/quote]

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Posted by BATMAN on Wednesday, July 21, 2021 4:28 PM

snjroy

I'm still waiting to see the Batcave on that layout Smile

Simon

 

Now that's a cool idea!Laugh

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 


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Posted by JDawg on Wednesday, July 21, 2021 3:42 PM

Holy color Batman! I think we need sunglasses!

JJF


Prototypically modeling the Great Northern in Minnesota with just a hint of freelancing. Smile, Wink & Grin

Yesterday is History.

Tomorrow is a Mystery.

But today is a Gift, that is why it is called the Present. 

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Posted by snjroy on Wednesday, July 21, 2021 3:13 PM

I'm still waiting to see the Batcave on that layout Smile

Simon

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Posted by SeeYou190 on Wednesday, July 21, 2021 2:59 PM

BATMAN
I think those curtains are developing a cult following

No doubt, and they add personality to the layout room.

They look both completely out-of-place and like they belong there at the same time.

-Kevin

Happily modeling in HO scale. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by BATMAN on Wednesday, July 21, 2021 2:34 PM

SeeYou190

Awwww...

You cropped this picture so we can't see the curtains.

Sad

-Kevin

 

There you go Kevin, along with the final resting place of the Bat-O-Template. Having that template sure made things easy.

I think those curtains are developing a cult following as I also get comments on FB.Laugh

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 


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Posted by SeeYou190 on Wednesday, July 21, 2021 1:54 PM

Awwww...

You cropped this picture so we can't see the curtains.

Sad

-Kevin

Happily modeling in HO scale. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by BATMAN on Wednesday, July 21, 2021 1:43 PM

Lastspikemike
Sure but in order to locate the position of the turntable you must first know exactly where the roundhouse is to go. The issue is locating the centre of the turntable before you "position" it.

And that is where the Bat-0-template works well, incorporating the printed Walthers template. You can move it all over the place and when you're ready put a pinhole through the centre of the TT to mark the spot.

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 


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Posted by Lastspikemike on Wednesday, July 21, 2021 1:38 PM

richhotrain

Always position the turntable first.

 

Sure but in order to locate the position of the turntable you must first know exactly where the roundhouse is to go. The issue is locating the centre of the turntable before you "position" it. Obviously you cut the hole for the turntable before you secure the roundhouse in position. But you use the roundhouse position to find the position of the  center of the turntable before you cut that hole. 

Alyth Yard

Canada

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Posted by snjroy on Wednesday, July 21, 2021 11:04 AM

I had a very tight space for my turntable and roundhouse, so the template provided by Walthers was very useful for me to position both structures properly in the space I had. The turntable plus surrounding tracks can take a lot of real estate... I installed the turntable first, then the roundhouse, then I adjusted the tracks while the roundhouse was still floating on the layout. My margin of error was only about 1 inch, so it was crucial for me to plan it correctly. I programmed the turntable, and when I was satisfied with it, I nailed the tracks to stabilize everything.  That was three years ago - no problems since.

Simon

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Posted by RR_Mel on Wednesday, July 21, 2021 10:45 AM

I’ve built five turntable/roundhouse combinations over 50 years and installing the turntable first works out far better.  Four were scratch built turntables.

This is my last scratch built turntable bridge & superstructure in 1992.



My final turntable is a 135’ CMR kit which really works great.



The CMR turntable did not come with the superstructure so I did my scratch build thing using a Central Valley Bridge & Girders 1902-5 kit.





I used the October 1989 MR Centerfold as a go by.


 
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 SeeYou190 on Wednesday, July 21, 2021 9:05 AM

richhotrain
Always position the turntable first.

Agreed, and then using a laser like Ed showed in his pictures looks like that would make roundhouse alignment right on the money very easily.

-Kevin

Happily modeling in HO scale. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by richhotrain on Wednesday, July 21, 2021 8:28 AM

Always position the turntable first.

Alton Junction

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Posted by SeeYou190 on Wednesday, July 21, 2021 8:28 AM

gmpullman
Well, honestly, I really didn't give much consideration to thermal expansion on a 130' turntable.

I do not give thought about thermal expansion to anything.

My layouts have always been in the climate controlled section of the house, and this is not a factor.

-Kevin

Happily modeling in HO scale. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by Lastspikemike on Wednesday, July 21, 2021 8:23 AM

My view is that the roundhouse is located first. Messing around with the two templates revealed this to us. You don't actually need a turntable template. A tape or meter stick will tell you if there's enough room for the turntable. We cut the turntable circle template not realizing we didn't need one. You do need to allow for the turntable approach track(s). We quickly discovered that the length of this approach track is the most likely limiting factor for fitting in a roundhouse. 

Place the roundhouse, draw two lines (or three if you're a woodworker, always three) and that marks the center of the turntable. Cut your turntable hole using that center for whatever circle cutting guide you are using.

Presto, the length of the required connecting tracks  can be measured directly on the layout. 

Allow a fudge factor of say 1/2" to finally locate the roundhouse after you actually cut the hole for the turntable allowing for cutting errors. The stall angles require the roundhouse to be exactly x" from the turntable. Cut those connecting tracks to fit leaving the required larger than usual gap between the bridge track ends and the connecting track ends. I think Walthers recommends tapering the inside edges of the turntable ends of the connecting track rails to facilitate transit of the locomotive wheels across these gaps. 

We'll find out if all this works.

Alyth Yard

Canada

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Posted by richhotrain on Wednesday, July 21, 2021 6:46 AM

Lastspikemike

I remain sceptical. I plan to use my simple method to install my turntable and roundhouse. I'll let you know how that goes if and when we get around to it. So far we just have two paper templates. One circle and one wedge shape.  

Remaining skeptical is a good sign in that it indicates that you might be persuaded otherwise. So, we look forward to learning the results of your approach.

Since you indicate that you have two paper templates, a circle and a wedge shape, you have already improved upon the two-line approach by adding in the radius of the turntable pit.

I assume that the wedge shape is the stall floor and that the circle represents the circumference of the turntable pit. Without that circumference, you don't know the radius, so you don't know how far to place the roundhouse from the turntable.

Alton Junction

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Posted by SeeYou190 on Tuesday, July 20, 2021 11:51 PM

RR_Mel
That gave me the incentive to draw up a couple of to scale top view drawings of my articulated locomotives.  I’ve been wanting to do that for several years.

Nicely done.

I like the cab forward and cab normal graphics.

-Kevin

Happily modeling in HO scale. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by RR_Mel on Tuesday, July 20, 2021 8:24 PM

JDawg

I am trying to plan for a roundhouse/turntable on my condo layout. I am looking at the walthers 90ft and the matching roundhouse. How much space is there between the Turntable and the roundhouse. My calculations show about a foot between, but that seems extreme. How much space should I plan for?

 

I want to thank you for this topic!!!!  That gave me the incentive to draw up a couple of to scale top view drawings of my articulated locomotives.  I’ve been wanting to do that for several years.



The two locomotives are 18”+ and fit my kitbashed/lengthened Korber Roundhouse nicely.



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 richhotrain on Tuesday, July 20, 2021 6:03 PM

Here is a good takeaway when installing a turntable and roundhouse. 

Once you determine the length of the connecting tracks by using the formula, you now know the approximate space required to install the turntable/roundhouse complex.

Then, you can install the turntable. Once that is done, you can finesse the roundhouse into place by aligning both ends of the front of the roundhouse to the exact distance determined by the formula, after taking into account the fact that the connecting tracks need to extend over the lip of the turntable to the edge of the turntable pit.

Next, you can install the connecting tracks, all cut to the exact length determined by the formula.

Finally, you can test the rotation of the turntable bridge to see if the ends of the connecting tracks need to be filed to permit proper rotation of the turntable bridge.

Rich

Alton Junction

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Posted by richhotrain on Tuesday, July 20, 2021 5:58 PM

Lastspikemike

And approximately isn't going to work when actually fitting the track. I fit my joints pretty much with no gap at room temperature. No matter how accurately you try to cut and fit there will always be a bit of a gap somewhere big enough to accommodate thermally induced rail length changes. 

Truth be told, there will always be a gap between the bridge rails and the rails on the connecting track, no matter how infinitesimal. If there weren't, every time the bridge track rotated across a connecting track, it would snag unless the cut were so exact that only a slight gap of paper width were made at the end of the connecting track. 

Alton Junction

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Posted by Lastspikemike on Tuesday, July 20, 2021 5:53 PM

My point was about the size of any rail joint, not at turntables specifically. The rail gap between the turntable and connecting track has to be wider than would otherwise be correct in order to accommodate the swing of the gauge. The base of the ends of the rails on the bridge will conflict with those on the connecting tracks. That gap needs to be accurately made.

Sure, if you can measure accurately, allow for the necessary gap and cut all rails exsctiy the same and then position the roundhouse exactly correctly you might use a formula to calculate the cut length of your connecting tracks.

I remain sceptical. I plan to use my simple method to install my turntable and roundhouse. I'll let you know how that goes if and when we get around to it. So far we just have two paper templates. One circle and one wedge shape. 

Alyth Yard

Canada

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Posted by richhotrain on Tuesday, July 20, 2021 5:52 PM

Lastspikemike

Just a reminder to other readers trying to use all of this information: 7/16" is basically half an inch. That's a big gap.

Before we all get lathered up about a 7/16" gap, let's recall that the 7/16" measurement was a guesstimate between Pruitt's indication that the dimension from the center of the turntable to the doors is 11 15/16".

Kevin indicated that the 90 foot turntable bridge is about 13" long, or 6 1/2" to center. That should give you about 5 1/2" of track between the turntable and the roundhouse.

Turns out, the exact distance was 5 1/16", or 7/16" difference. Not bad for a guesstimate. After all, JDawg's original estimate was 12". That's the beauty of the formula - - exactness.

Lastspikemike

Use the same techniques to cut and fit roundhouse connecting track as you would for any track fitting. You don't need to know how long the track needed is, just use a piece long enough to cut to fit. You could cut all the pieces from just one instance.  They all should be exactly the same but only if you're  very accurate in your placement of the roundhouse and turntable. Mind you, using lengths of connecting track all cut exactly the same from the one example should orient your roundhouse to the turntable very accurately. 

And that is why the forumula is so useful. It tells you the exact distance between the edge of the pit on the turntable and the front floor of the stalls.

In fact, once the formula provides the exact distance, that measurement can be used to perfectly align the roundhouse with the turntable.

Each and every connecting track will be the exact same distance whether the outermost stall or the middle stall or any other stall in between.

The shortcoming of your two-line theory is that it fails to identify that exact distance. It only tells you the distance from the centerpoint of the turntable to the round stall floor. You still need to know the radius of the pit to determine the exact length of the connecting track - - every connecting track.

Alton Junction

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Posted by gmpullman on Tuesday, July 20, 2021 3:13 PM

Lastspikemike
No matter how accurately you try to cut and fit there will always be a bit of a gap somewhere big enough to accommodate thermally induced rail length changes.

Well, honestly, I really didn't give much consideration to thermal expansion on a 130' turntable.

I simply left each rail about a quarter inch (6.35 mm) longer than necessary then trimmed each one after the roundhouse was set in place.

 Pit_Rail by Edmund, on Flickr

Once trimmed and filed I set the base of each rail into a dab of epoxy. This is my second, nine-stall roundhouse at this location. The turntable and original Heljan roundhouse was installed in 1995.

 Pit_Rail_crop by Edmund, on Flickr

You can see that there is a bit of a gap in the closest track. This was easily pulled down (weighted) once the rail ends were trimmed and filed (a slight relief was filed into the gauge-side of the rail head) and a bit of epoxy was applied.

The 'new' roundhouse has been in place since April of 2018 and has not shown any signs of misalignment or thermal activity.

Good Luck, Ed

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Posted by SeeYou190 on Tuesday, July 20, 2021 2:29 PM

richhotrain
You may have been closer than that, Kevin

Woo Hoo!

Kevin for the win!

Idea

-Kevin

Happily modeling in HO scale. A Class A line located in a personal fantasy world of semi-plausible nonsense on Tuesday, August 3rd, 1954.

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Posted by Lastspikemike on Tuesday, July 20, 2021 2:28 PM

Just a reminder to other readers trying to use all of this information: 7/16" is basically half an inch. That's a big gap.

And approximately isn't going to work when actually fitting the track. I fit my joints pretty much with no gap at room temperature. No matter how accurately you try to cut and fit there will always be a bit of a gap somewhere big enough to accommodate thermally induced rail length changes. 

Use the same techniques to cut and fit roundhouse connecting track as you would for any track fitting. You don't need to know how long the track needed is, just use a piece long enough to cut to fit. You could cut all the pieces from just one instance.  They all should be exactly the same but only if you're  very accurate in your placement of the roundhouse and turntable. Mind you, using lengths of connecting track all cut exactly the same from the one example should orient your roundhouse to the turntable very accurately.

Alyth Yard

Canada

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Posted by richhotrain on Tuesday, July 20, 2021 1:44 PM

You may have been closer than that, Kevin, since that measurement is from the outer lip of the turntable, but the connecting track needs to reach the pit to connect to the bridge track. So, the connecting track would be about 5.775".

Rich

 

Alton Junction

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Posted by BATMAN on Tuesday, July 20, 2021 1:40 PM

snjroy

Hi there. This is what I got when I purchased the 90' turntable - or was it the roundhouse??? Anyway, it says that this applies to both the modern and regular Walthers roundhouse. I can't find it on the Walthers Website. Maybe the model was changed or there was a mistake... Anyway, here it is:

 Walters 90 footprint on Flickr

Simon

 

Yes, this is what I got as well, I did not have to use my poor B+ grade 12 math skills. Just remember the track goes to the pit edge, not the edge of the lip so that is likely how I ended up with 30cm, pit centre to front edge of the RH.

Brent

It's not the age honey, it's the mileage.

https://www.youtube.com/user/BATTRAIN1/videos 


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Posted by richhotrain on Tuesday, July 20, 2021 1:39 PM

snjroy

Hi there. This is what I got when I purchased the 90' turntable - or was it the roundhouse??? Anyway, it says that this applies to both the modern and regular Walthers roundhouse. I can't find it on the Walthers Website. Maybe the model was changed or there was a mistake... Anyway, here it is:

 Walters 90 footprint on Flickr

Simon

 

This may be what Brent was referring to. I have the original 130' non-DCC turntable, and there are no distance measurements from the turntable to the roundhouse.

Rich

Alton Junction

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