Fun with scale curvature

[jereising]

I'll just drop this here...

[thbguy]

@thbguy, inner curve here is 19", I tried to keep it 'fair' buy using similar-sized cars and locos:




Turns out 19" is what I used on the mainline for my little Loop layout.  Still a substantial difference, tho lower viewing angle and finished scenery do help.  I think a finished scene helps the brain to compensate, at least to some degree:

Of course, my whole little Loop layout would have fit onto that single 4x8 foamboard. 

Ed

Thank you very much for the comparison.

Hmm, I think that it really comes down to that it all depends on your track height.
A drone’s eye view will look like a model even on the prototype.
And whether the track curvature is tight enough to affect performance.

We do all we can with the space we have!

Best regards, Michael

[ednadolski]

Atlas code 55 sectional track is available in up to a 71" radius:

Works out to about a 6-degree prototype curve: http://www.urbaneagle.com/data/deg-curve.txt

Ed

[ednadolski]

A drone’s eye view will look like a model even on the prototype.

Very true! 

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Ed

[Mark W]

This would be a good radius for Free-moN @Mark W

Yeah, Free-moN allows 22" minimum radius, but aside from my return loops, my average module radius is closer to 75" radius.

Starting at the bottom and going toward the wind turbines:
108" left
106" right
48" left
175" right
48" left
22" return loop


https://i.imgur.com/cdcdRCQ.jpg

Another trick I think this picture plays is those wind turbine heights!  They look huge right?  But wait, those are actually Z scale sized wind turbines on an N scale layout.  A properly sized modern N Scale turbine would stand about 3 feet tall! 

[Cameron_Talley]

For some reason height never scales well to me.  The same problem with trees.  Real scale trees look freakishly tall for some reason.  I'd rather have something "look right" or evoke the right feeling even if it's not 100% in scale.  Those turbines are the perfect example of that.

[ednadolski]

Same train on a smaller curve:  28 3/4" radius which is 2/3 the full scale size (equivalent prototype size is a 15-degree curve).

While far more practical and manageable, I dunno, it just doesn't seem to have nearly the same impact as the full-size.  Maybe part of it is that the train at the same speed takes significantly less time to traverse the same arc of the circle.  In person, it definitely feels snug once you start getting used to the full-size, tho not as claustrophobically so as the 19".... 

Ed

[Point353]

Same train on a smaller curve:  28 3/4" radius which is 2/3 the full scale size (equivalent prototype size is a 15-degree curve).

28 3/4" is approximately (actually 29") the radius of the curve for the branch line (innermost of the usual three tracks) on an NTRAK four-foot corner module.

[Maletrain]

To me, at least, the "toy train" visual effect of model railroad curves has more to do with the abruptness of the change from straight to curve.  So, using reasonable length spiral transitions between straight and constant radius curves seems to make the "flow" appear much more realistic, even though the curves are substantially tighter than prototype.  Not only the appearance of the unoccupied track, but the motion of the trains over the track seems to flow much better.

Spiral transitions don't add much to the total diameter of a 180 degree turn-back, so they do not require significantly more layout width.  But, they do add substantially to the length of the curve, or maybe I should say they subtract from the length of the straighaways between curves on a layout.  That can be an issue when trying to fit a bunch of turnouts between two curves.

[randgust]

It's really hard to do it justice, it's something that never translates well from actual prototype to model, but we can do the best we can in N scale and at least to better than the HO guys.    I remember in HO everything was an 18" or 22" curve, 40' boxcars normal, a six-axle Athearn diesel looked huge, so did 50-footers.   85' passenger cars looked a little crazy.    So N scale going up to a 15" curve standard seemed like a miracle for my layout design, because you still think in HO terms.

Now, having worked in the industry for 27 years,  the 30-degree High Falls Curve on the West Virginia Central (ex-WM Elkins to Spruce) still holds the title for me, and that works out to 193 foot radius; 14 1/2" - is so sharp that the Suburban hirail truck I was riding in fell off the railhead on the inside of the curve while the hirail wheels were still on the rails.  'have to keep it to at least 20mph, and don't slow down' was the CSX recommendation that didn't get followed that day.   And they still run 85' cars around that curve on the Salamander.   Look at it on Google Earth, it's quite the absurd 180-degree curve around a mountain where they were just too cheap as a logging railroad to drill a tunnel.
Here's what it looks like from the ground: 
https://www.railroadphotographer.com/Railroads/A-Railroad-Portfolio/Heritage-Railroading/Museums-and-Tourist-Railroads/West-Virginia-Central/i-bHmW8vS/A

The 'normal' tight standard I see is 14-degree, which has appeared to be the PRR minimum radius for wye tracks, etc.  Works out to 410 feet or around 30 inches in N.  I'm not sure anybody with anything less than a gymnasium could live with that.   But we can all dream.

Wide curves are always better in N, period, but to me, I'm just glad not to be in HO!  But I'm still stuck in a small room.

[Cajonpassfan]

...

Wide curves are always better in N, period, but to me, I'm just glad not to be in HO!  But I'm still stuck in a small room.

Yes. And even if our minimums are too tight by proto standards, it doesn’t hurt to throw in wider curves where we can, with transitions. This one is about 57”...
Otto K.

[GimpLizard]

...the 30-degree High Falls Curve on the West Virginia Central (ex-WM Elkins to Spruce)...

https://www.google.com/maps/search/High+Falls+Curve,+West+Virginia/@38.7716743,-79.7786947,327m/data=!3m1!1e3?hl=en

Yeozza, that's tight. Looks to be at least a couple more, in that area, almost equally as tight.

https://www.google.com/maps/search/High+Falls+Curve,+West+Virginia/@38.7770141,-79.7702091,211m/data=!3m1!1e3?hl=en

https://www.google.com/maps/search/High+Falls+Curve,+West+Virginia/@38.7503585,-79.7892153,252m/data=!3m1!1e3?hl=en

[davefoxx]

Wow!  Ed's law is alive and well.  Those overhead shots are great, because there's no distortion due to perspective.  Wow!

DFF

[Sokramiketes]

[ Laughs in Free-moN ] 

LOL, yeah the modular guys figured this out a long time ago.  Modutrak is 54" for reference.  Just wish the corners weren't such a bear to haul around and store at that size. 

Once you get a passenger train out there, you're spoiled and nothing else is good enough.

[robert3985]

20 years ago, or thereabouts, when designing Echo Yard, I wanted to make it as prototypical as I could in 18'.  One of the features of the yard is that it is kinked in the middle, and I wanted to include that in my model of it. 

Luckily, one of the residents, and owner of one of the cafes on the highway going through the town of Echo, was also interested in the history of the place and I happened to be talking to him over a steak and egg breakfast he had just cooked for me early one late March morning.  He brought out a valuation map of the Echo Yard and town that had measurements of all of the town buildings as well as the UP structures, turnout sizes and rail curvatures...and a lot more.  An absolutely priceless find for me!  He had more than one copy and gave me one, and so I included my Echo Yard "kink" in my selectively compressed version of the yard and town, keeping the actual curvatures of the rails of both mainlines and yard trackage accurately.

I don't remember the degree of curvature on the valuation map, and I'm not gonna go get it to look, but the curvature of the "inside" track (of five tracks) converted to N-scale is 105.7".

Photo (1) - 105.7" Radius Curve with a 30 car Reefer Block at Echo Yard on My Layout:


Photo (2) - Big Boy and Reefer Block on West Bound Mainline Track at Echo Utah with 29 Reefers Visible:


Regretably I didn't superelevate the two mainline tracks on these curves on my Echo LDE, but as you can see from the prototype photo, superelevation was minimal.

Yup, John Armstrong was completely correct to attempt to have a "Photogenic curve" in every layout.  They look good, trains run great on 'em and are definitely worth the effort to include.

Cheerio!
Bob Gilmore