# Engine requires 8 foot curves or turn arounds?



## johnssleepingnow (Feb 27, 2010)

If the engine I might purchase needs an 8 foot turn around can I use pieces of a 4 foot turn around or R2 curves to avoid trees or large objects in my yard? Do I have to use pieces of 8 foot curves to avoid derailing? I think I need to figure this out before purchasing train or track? I don't know how to convert R2 curves to foot turnarounds but it sounds like it is a 5 foot curve?


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## Greg Elmassian (Jan 3, 2008)

8 foot diameter is around LGB size R3

See the chart on this page and pay careful attention to radius vs. diameter.

*http://www.elmassian.com/trains-mai...a-switches* 


Normally if your engine requires 8 foot diameter, 4 foot is out of the question.


R2 is about 5 foot diameter.

What locomotive is it? There's lots of experience on this site, and we can double check the real minimum diameter it will take.

As an aside, you should be striving for the largest diameter curves you can fit. Take some extra time and try to figure it out. 

When I started my layout, it seemed I could only use 8 foot, but working at it a bit, I was able to raise that to 10 foot. I can run 95% of the locomotives out there.

Regards, Greg


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## Dan Pierce (Jan 2, 2008)

LGB R2 is around 5 foot diameter, Train-Li is 6 foot diameter/ 

These are really center to center measurements in millimeters and are rounded off. 

1200mm track is really about 47 3/8 inches, not 4 foot. Makes a difference for some when doing exact planning. 

Some large engines will traverse 4 foot diameter track, but the overhang places the coupler outside the rails and will derail any cars attached to the engine. 

Wider curves are always better.


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## johnssleepingnow (Feb 27, 2010)

thanks for your help guys!


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## SE18 (Feb 21, 2008)

make blind drivers


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## chuck n (Jan 2, 2008)

There are engines and trains that look fine on R1 and R2 curves. These are engines and cars with very short wheelbases. It would help us help you if you could say what type of trains you are interested in running.

Over the years, my first outside layout was with R2 (5' diameter). It was fine, but when I expanded to another loop on a higher terrace I used R3 (8' diameter). The trains I was running looked better with the wider curves.


When I moved to Virginia in 1993, I used Aristo 10' diameter for my current layout. I am giving serious thought to redoing it with 20 foot curves. I run a mixture of Narrow Gauge (1:20.3) and almost modern standard gauge (late steam and early diesel). I think that what I currently run would look better on a layout with 20' diameter curves and #6 switches. We just have to decide how long we are going to stay in northern Virginia.


As others have said, go with the widest radius that you can fit into the space and still give you a layout that you can enjoy. Be sure to make any passing siding long enough for your future trains. My rule of thumb is to make them at least 50% longer than you think your longest train will ever be. In my case I have lengthened the siding twice. It is all that healthy sunshine and rain that makes the garden railways grow larger than you think they will grow. 


Chuck 


PS There are a lot of people on this website who live all over the country. Most of us would be happy to talk to you and help you with your trip into Garden Railroads. In what part of the country do you live? Most areas have active garden railroad clubs, These are an excellent source of information for those starting out in this hobby. If you live in Barrow, Alaska your nearest help in in southeastern Alaska, but other than there you probably aren't very far from someone who can help you get started. Just remember, all the mistakes have already been made, use this site and your local MLSers to help you keep from making the same mistakes.


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## lownote (Jan 3, 2008)

What Chuck said. Some engines can run below their minimum curve. Most can't, and they derail right away, as soon as they hit that tight curve.


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## pimanjc (Jan 2, 2008)

John,

As was previously said: "Some engines can run below their minimum curve. Most can't, and they derail right away, as soon as they hit that tight curve. " Sometimes an 8ft diameter rated loco, by itself, can travel around a 5ft [R2] curve. However, you may find out that when a car is coupled behind it, the attached car always/frequently derails. In that case, you still need the 8ft minimum. 

I have locos that fit both cases. My brass Accucraft K-4 loco is rated as 8ft minimum. The video below shows what can happen when a piece of 6.5ft diameter curve is placed in an otherwise 8ft diameter curve, to get around a tree. After the 6.5ft piece was replaced with an 8ft [R3] curve and the connecting adjustments were made, there were no more derails. 



Direct youtube link: http://www.youtube.com/watch?v=LuWA5JV6KvY

Once, when I was just beginning to seriously get involved in this hobby, Marty Cozad wisely explained to me "that the minimum curve diameter is determined by the tightest [smallest diameter] curve OR switch, anywhere on the layout." 

..... Last weekend, I was running my M-190 kitbashed articulated doodlebug on a friend's RR during a seminar on RC systems. The friend said that the minimum curves were R3 [8ft diameter]. The M-190 was built with the ability to traverse 5ft diameter curves. However, all of the crossovers between loops on the layout were made with back to back R1 [4ft diameter] switches. Between the tight diameter switches and the compounding problem of an "S" curve without a straight piece in the middle, the M-190 derailed every time an attempt to change loops was made.

Hope this helps.

Jim C.


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## Tom Leaton (Apr 26, 2008)

The answer to your first question is: no. 

cheers 

TUL


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## Randy Stone (Jan 2, 2008)

Another thing to consider, some long diesels will traverse 4 or 5 ft diameter curvers without derailing when run by themselves. But, hook some frt cars or passenger cars to it and there is a derailment. The reason is over hang. If the coupler is hanging over the outside rail in a curve, there typically will be derailments when cars are in tow. 

Randy


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## blueregal (Jan 3, 2008)

Never ever use anything less than 10ft or more curves!! You'll be happy ya did believe me!! 20's better!! Regal


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## Randy Stone (Jan 2, 2008)

So Regal, you're telling newbies they should go run HO if they don't have room for 10 foot curves? 

Not everyone has room for 10 foot curves. 

A lot of members on this site run 4 ft curves and have a blast doing so. 

You run what you can. 

Randy


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## Larry Walkley (Oct 25, 2011)

out of curiosity, i have the 4 foot curves due to room and am curious what 5 foot curve engines, if any, will navigate the 4 foot curves with the hook and look couplers which is what my stuff is running. i have already settled on the nw-2 but wouldn't mind something a little bigger if it works. all my cars are a foot or so in length if that makes any difference.


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## Dan Pierce (Jan 2, 2008)

Any LGB engine will run on 4 foot diameter curves. However the genisis derailed the first freight car. 

I have run Aristo FA's, Bachman annies with the pilot truck weighted on 2 foot radius with no derailemnts. 

Even the SD45 will go around my indoor layout which is all 2 foot diameter, but no cars can be attached directly. I built a tow bar and can haul freight on my indoor layout with SD-45s.


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## Larry Walkley (Oct 25, 2011)

A tow bar? How did you do that? I was thinking that I would really like a GP-38 or -40 or a RS-3 but nothing bigger than that. I like the longer trains so a dual motor unit would be ideal for me.


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## blueregal (Jan 3, 2008)

Posted By rlvette on 03 Mar 2010 10:44 AM 
So Regal, you're telling newbies they should go run HO if they don't have room for 10 foot curves? 

Not everyone has room for 10 foot curves. 

A lot of members on this site run 4 ft curves and have a blast doing so. 

You run what you can. 

Randy 

Randy, I am only talking from my personal experience, and what a retailer advised me of when I first got started in this hobby, and I am glad I listened to him, 10ft. is the minimum for me and I would tell anyone that. My experience is a ceiling layout, and an outdoor layout of 500ft. I wish I would have went with 20ft. or bigger, it all depends on what you like running almost anything except LGB, and Bachmann require 10ft. diameter curves, like my mallet, and dash 9's, and my K, any smaller and they wouldn't be able to be run. 

My opinion, run what you want its your railroad, 10ft. is minimum, if you don't want to be sorry later IMHO!! Regal 


p.s. I am talking about 10ft. diameter curves which are 5ft. radius!!


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## aceinspp (Jan 2, 2008)

The RS3 does have considerable coupler swing on 4 ft diameter and will pull cars of the track. Later RJD


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## Ron Hill (Sep 25, 2008)

My curves on the layout is 8 foot radius. I tried to run a GP-30 on a 2 foot radius curve and the tires came off. 
ron


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## Larry Walkley (Oct 25, 2011)

I started thinking last night that maybe another Alco A/B set would be the way the go again. I already know it runs great and I will get a roadname other than Santa Fe just to have something different. Thanks for all the help guys.


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