Author Topic: 15" curves and full circle  (Read 982 times)

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h2w

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15" curves and full circle
« on: July 26, 2015, 03:55:13 PM »
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ok I have atlas 15 incurves if my math is correct  a full circle  should fit on a 30 inch x 30 inch board. well I have a 30 inch wide door and the turn back curve is half a circle the track goes off the door an inch and a half, so am I missing something?

wcfn100

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Re: 15" curves and full circle
« Reply #1 on: July 26, 2015, 05:00:12 PM »
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The radius of a curve is traditionally measured at the center line of the track so you would have least one width of whatever track you're using that would exceed a 30" space. 

You don't mention which Atlas track you're using, perhaps they measure from a different point like the inner rail or the inner edge of the roadbed for the True-track.  But even with that, an inch and a half is more than even the True-Track should hang over it think, have you measured the door to make sure it's actually 30"?

Jason

wcfn100

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Re: 15" curves and full circle
« Reply #2 on: July 26, 2015, 05:18:16 PM »
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Okay I just saw this was HO.  It's just that the curve is measured on center which will always leave a full track width wider than the radius.


Jason

cv_acr

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Re: 15" curves and full circle
« Reply #3 on: July 30, 2015, 03:35:43 PM »
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Yeah, so minimum 32" table width and 15" is insanely sharp for anything but streetcar track or a micro-layout with critter locomotives and tiny cars.

Unless you actually meant to post this in N scale.

lajmdlr

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Re: 15" curves and full circle
« Reply #4 on: July 31, 2015, 09:43:56 AM »
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There are prototypes for VERY sharp curves. The narrow gauge Uintah Ry had some 65 degree curves on a 7.5% grade. They ran 2-6-6-2s there. The Los Angeles Junction Ry has a place w/ a 85 degree curve (10"R HO) plus a #3 switch. To test that laid down a 1/4 10"R curve & was able to run an HO Athearn CF7 & Atlas S-2 plus a  40' boxcar around it in both directions w/ no problems. Couldn't do it w/ av 50' car though. >)
Andy Jackson
Santa Fe Springs CA
LAJ Modeler

avel

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Re: 15" curves and full circle
« Reply #5 on: August 01, 2015, 12:05:17 AM »
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I just tested an Athearn RTR sw1500 around a 12.5"R and it ran fine. It can pull and push an Atlas 3560 3 bay hopper, but coupling on a curve is hard, and the trip pin on the car hits the sw1500 body. So with short cars you can go pretty tight, but it won't look realistic, and you'll be limited to shorter equipment.
iamaman27 on the youtubes

h2w

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Re: 15" curves and full circle
« Reply #6 on: August 01, 2015, 01:23:06 AM »
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Thank you or the tips, yes ITs going to be HO scale i have run an atlas gp7 plus 3-4 50' boxcars it runs great push or pull. the return curves on each end will be partialy blocked so the over hang won't be a problem. i will be using small switchers and gp7s and gp9s.
thanks or the help

glakedylan

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Re: 15" curves and full circle
« Reply #7 on: August 01, 2015, 04:01:20 PM »
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if it is at all possible, and space permits
entering into each 180 degree 15" radius curve
with a 18" radius section will provide easement
and better operation
you do not have to use a full length section
just cut track to fit, even if it is but 10 degrees
it really does make a difference
thanks for sharing here
much appreciated
sincerely--
Gary
PRRT&HS #9304 | PHILLY CHAPTER #2384

nkalanaga

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Re: 15" curves and full circle
« Reply #8 on: August 02, 2015, 12:51:17 AM »
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Back in grade school, many years ago, we took a field trip to Yakima, WA.  I don't remember anything about the museum we went to, including the name.  I do remember being "stuck" at an intersection by a train.

The Yakima Valley Transportation Company, an interurban kine, was still in the freight business, serving mostly fruit packing houses west and north of Yakima.  To get the cars from the UP/BN interchanges to the customers they had to go through Yakima, on the original streetcar tracks.  We sat there for quite a while as they tried to get an 89 ft flatcar around a street corner.  The track was entirely in the streets, so it had to be a sharp curve, and took a lot of work.

They had uncoupled the car before we arrived, and attached a chain to both couplers.  While we sat there, they crawled under the flatcar, disconnecting the brake rods from the trucks.  Then the creased the rails, and VERY slowly pulled the car around the curve, with much screeching and groaning.  I don't imagine they were looking forward to having to bring it back later.

I think there were two of us kids that watched the show, the other being a girl I knew, whose father I found out later was also a model railroader.  The rest were bored, and talked or played games.  The bus driver just sat there looking annoyed.
N Kalanaga
Be well