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What's a 13' Turn? Locos and rolling stock
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Active Member 33 posts eufonist Active Member 33 posts
eufonist

Hi,

I'm thinking about to buy the Zephyr Kato N 106090-2 Chicago Burlington and Quincy EMD E5A and Silver Streak. I asked a dealer about the minimum radius and he answered: "The minimum radius is a 13' turn as the tightest turns possible for this set." In Germany we measure the radius in millimeters and I would have understood an answer in inches. But what does a 13' turn mean? 13 ft? That's about 4 meters, that can't be what he means.

Regards,
Stefan

Regards,
Stefan

N scale
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LKandO Prolific poster 3,839 posts
LKandO

13 inch radius would make

13 inch radius would make sense in N scale. Just sayin'.

Alan

All the details:  http://www.LKOrailroad.com        Just the highlights:  MRH blog

When I was a kid... no wait, I still do that. HO, 28x32, double deck, 1969, RailPro
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eufonist Active Member 33 posts
eufonist

Yes, I already thought about

Yes, I already thought about that, too. But that seemed to me to be a big curve. But it might be true. Probably this is the recommended minimum radius and I wonder what the actual minimum is. I have several locos with 6 axles like this one that run a 7.5" radius without any problems.

Regards,
Stefan

N scale
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ratled Frequent poster 926 posts
ratled

Degrees not length?

Just a guess on  my part but could they have meant a 13 degree curve like used on turnouts?

Steve

http://klamathline.blogspot.com/

 
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eufonist Active Member 33 posts
eufonist

That was my other thought

That was my other thought because of the word "turn". If so, how big is the radius then?

Regards,
Stefan

N scale
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eufonist Active Member 33 posts
eufonist

I just found this

I just found this information: http://katousa.com/cgi-bin/dl/dl.pl?dl.mif,MRN0113-Preview.pdfIt says "Kato’s streamliners include truck-mounted knuckle couplers, which allow the cars to navigate tight-radius curves." Whatever tight is. I think I will give it a try.

Regards,
Stefan

N scale
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Athlon Regular poster 194 posts
Athlon

I believe you can have any

I believe you can have any degree with any radius.  One does not create the other.  

For example, you can have a 7" radius with a 45 degree turn or a 90 degree turn, or any degree from 0 to 360..  A 7" radius with a 360 degree turn would be a perfect circle.  The same would be true with a 13" radius and a 360 degree turn.  You would just have a larger circle.

My guess is he either meant 13", or 13 scale feet in what ever scale you are modeling.

 

 

Dave
Uxbridge, MA

How I Installed An NCE USB Adaptor Into My Fascia
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Milt Spanton mspanton Super User 979 posts
Milt Spanton mspanton

Degrees Versus Radius

See this table.  It is how many degrees curve for a given length.

http://www.trainweb.org/freemoslo/Modules/Tips-and-Techniques/degrees_of_curve_to_radius.htm

 

- Milt
The Duluth MISSABE and Iron Range Railway in the 50's - 1:87
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Crusty Old Shellback Regular poster 297 posts
Crusty Old Shellback

7.5" radius?

Are you sure about the 7.5" radius? That's like a 14" circle and even in N scale would be really tight. I'm using 16" radius curves on my layout and even with my 75' pullman passenger cars, I'm haveing a litte issue with them. I haven't taken a closer look yet to see exactly what is wrong. But I can tell you from the looks of them going thru the turn, it looks a little tight with a bit of overhang.

Have you checked the NMRA standard for the cars you want to run? I think a 13" radius turn will be a bit tight. It may work but will it look right?

My arms got too short so I've switched to G scale. Old steam and early diesel are my choice of loco. Scratch built is better.
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Athlon Regular poster 194 posts
Athlon

Milt - that table - what is it saying?

Milt - that table - what is the length of each piece of track?

Wouldn't the length of a piece of track be shorter if it turned 45 degrees with an 18" radius than a piece of track that turned 45 degrees with a 30" radius?

I don't understand that chart at all.......

Dave
Uxbridge, MA

How I Installed An NCE USB Adaptor Into My Fascia
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Russ Bellinis Prolific poster 3,335 posts
Russ Bellinis

Minimum radius has nothing to do with how it looks!

"Are you sure about the 7.5" radius? That's like a 14" circle and even in N scale would be really tight. I'm using 16" radius curves on my layout and even with my 75' pullman passenger cars, I'm haveing a litte issue with them. I haven't taken a closer look yet to see exactly what is wrong. But I can tell you from the looks of them going thru the turn, it looks a little tight with a bit of overhang."

The information published by Kato suggests that the train will go around a tight curve because it has talgo trucks.  That doesn't mean it will look good doing it.  It also doesn't mean that a modeler would find it more important to have the model and not worry about how it looks going around the curve.

I don't model in N-scale.  In ho a tight radius is typically 18 inch radius.  That would probably translate to about a 9 inch radius in N.
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eufonist Active Member 33 posts
eufonist

To be exact, the radius is

To be exact, the radius is 194.6 millimeters which is 7 2/3". I have this train set from Kato http://www.topslotsntrains.com/topslotsntrains/final.asp?ref=KATO-LEMKE-11405-N-SCALE-SBB-RAe-II-TEE-HISTORIC-GOTTARDO-6-CAR-TRAIN-PACK-&id=7898&manufacturer='KATO%20N%20Gauge' It runs the very tight curves without any problems. Ok, it doesn't look good but those curves are in the invisible area of my layout. I have to use those curves due to limited space. As the train sets are from the same manufacturer and are similar concerning the trucks and the connection between the cars I ordered the train set yesterday and hope the best. If not it might be a good reason to build an additional layout with wide curves.

Regards,
Stefan

N scale
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Milt Spanton mspanton Super User 979 posts
Milt Spanton mspanton

Very complex explanation

Here is a better treatise on the math involved

http://mysite.du.edu/~jcalvert/railway/degcurv.htm

Basically, the track survey crew used a 100 foot line and laid it out straight in the direction they wanted to curve.  Then they measured how much the curve differed from the 100-ft line at its mid-point.  Using charts (before calculators) they used the deflection distance to calculate the degree of curve.

I believe you are confusing degrees of a compass, that is, I turn 90 degrees to the right, versus how many degrees does a curve turn for a given length (as above, 100 feet).

Think of it like we do for turnout "numbering".  A number 8 switch (turnout) has a frog angle that is 1:8, no matter if I measure eight inches (with one inch spread) or eight feet (with 1 foot spread) or 8 cm (with 1 cm spread), as long as I use the same unit of measure for the spread.

The NMRA-referenced chart on my prior post gave a quick conversion to HO.  What does matter here is that the HO scale equivalent radius needs to be converted to N scale for the OP's issue.

Hope that helps rather than clouds the concept.

- Milt
The Duluth MISSABE and Iron Range Railway in the 50's - 1:87
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LKandO Prolific poster 3,839 posts
LKandO

Explains a Lot

Quote:

A 6° curve, about the sharpest that would be generally found on a main line, has a radius of 955.37 feet.
The sharpest curve that can be negotiated by normal diesel locomotives is not less than 250 ft radius, or 23°.

Degree of CurveRadius, Scale FeetRadius for HO (Inches)
6955.366131.623
23250.79334.552

Sure makes it clear why our trains take on a toy like appearance. By this our industrial sidings should be minimum radius of 34" while our mainline minimum radius should be 131".

Going to need a bigger basement!

Alan

All the details:  http://www.LKOrailroad.com        Just the highlights:  MRH blog

When I was a kid... no wait, I still do that. HO, 28x32, double deck, 1969, RailPro
nsparent.png 
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Milt Spanton mspanton Super User 979 posts
Milt Spanton mspanton

Bigger Basement

I have that problem with my layout all the time! 

Of course, all of my mainlines are laid to a 131" minimum radius...!  NOT!

- Milt
The Duluth MISSABE and Iron Range Railway in the 50's - 1:87
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