Bayfield Transfer RailwayIf the distance from the roundhouse to the turntable is long enough, you will get the tracks overlapping and there will be frogs in the approach tracks.
Right.
Here's an example, C&NW in Chicago:
CNW_RHcrop by Edmund, on Flickr
The LS&MS turntable at Ashtabula is so arranged that each rail has to be joined to the next, almost employing a "half-frog":
New York Central Railroad Ashtabula Roundhouse Turntable by Ashtabula Archive, on Flickr
Regards, Ed
gmpullmanThe LS&MS turntable at Ashtabula is so arranged that each rail has to be joined to the next, almost employing a "half-frog":
Now that would be a trick to wire so it worked right!
-Kevin
Living the dream.
SeeYou190 gmpullman The LS&MS turntable at Ashtabula is so arranged that each rail has to be joined to the next, almost employing a "half-frog": Now that would be a trick to wire so it worked right! -Kevin
gmpullman The LS&MS turntable at Ashtabula is so arranged that each rail has to be joined to the next, almost employing a "half-frog":
More like a Nightmare!
Thanks for all the help guys.
JJF
Prototypically modeling the Great Northern in Minnesota with just a hint of freelancing.
Yesterday is History.
Tomorrow is a Mystery.
But today is a Gift, that is why it is called the Present.
SeeYou190Now that would be a trick to wire so it worked right! -Kevin
HOLY FROG JUICERS!
Brent
"All of the world's problems are the result of the difference between how we think and how the world works."
BATMANHOLY FROG JUICERS!
At least a few hexes!
Lastspikemike richhotrain Lastspikemike The resulting distance has nothing to do with the size of the turntable. The smaller the turntable the longer the tracks will be. Aren't those two statements contradictory? The footprint of the turntable and roundhouse are determined by the roundhouse stall angle and length. The turntable size is not relevant to the calculations you need to make. If the turntable needs to be bigger than ideal because the roundhouse stalls are very long then connecting tracks could connect or cross, unless you also change the stall angle. Put another way: you don't need to know the length of the connecting tracks between the edge of the turntable and each roundhouse doorway. That number doesn't help you locate or install the roundhouse and turntable. You just cut those connecting tracks to fit after the roundhouse and turntable are in place just as you would for any layout. No complex calculation is required. The roundhouse location determines where the center of the turntable must go which in turn requires a certain length of connecting tracks. You never need to calculate the length of those connecting tracks.
richhotrain Lastspikemike The resulting distance has nothing to do with the size of the turntable. The smaller the turntable the longer the tracks will be. Aren't those two statements contradictory?
Lastspikemike The resulting distance has nothing to do with the size of the turntable. The smaller the turntable the longer the tracks will be.
The resulting distance has nothing to do with the size of the turntable.
The smaller the turntable the longer the tracks will be.
Aren't those two statements contradictory?
The footprint of the turntable and roundhouse are determined by the roundhouse stall angle and length. The turntable size is not relevant to the calculations you need to make. If the turntable needs to be bigger than ideal because the roundhouse stalls are very long then connecting tracks could connect or cross, unless you also change the stall angle.
Put another way: you don't need to know the length of the connecting tracks between the edge of the turntable and each roundhouse doorway. That number doesn't help you locate or install the roundhouse and turntable.
You just cut those connecting tracks to fit after the roundhouse and turntable are in place just as you would for any layout.
No complex calculation is required. The roundhouse location determines where the center of the turntable must go which in turn requires a certain length of connecting tracks. You never need to calculate the length of those connecting tracks.
Alton Junction
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
snjroyHi there. This is what I got when I purchased the 90' turntable - or was it the roundhouse?
SeeYou190That should give you about 5 1/2" of track between the turntable and the roundhouse (if my math is OK).
Hey, I was only off by 7/16" with my estimate. Not too shabby.
Thanks for posting the drawing Simon.
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
Rich
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.
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".
richhotrainYou may have been closer than that, Kevin
Woo Hoo!
Kevin for the win!
LastspikemikeNo 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
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.
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.
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.
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.
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.
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.
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.
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.
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 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.
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.
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.
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.
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.
gmpullmanWell, 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.
Always position the turntable first.
richhotrainAlways 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.
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 http://melvineperry.blogspot.com/ Bakersfield, California I'm beginning to realize that aging is not for wimps.
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.
LastspikemikeSure 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.
Awwww...
You cropped this picture so we can't see the curtains.
SeeYou190 Awwww... You cropped this picture so we can't see the curtains. -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.
BATMANI 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.
I'm still waiting to see the Batcave on that layout
Holy color Batman! I think we need sunglasses!