# radius question



## bristolman2012 (Mar 4, 2012)

can u run 22 and 24 inch radius parallel to each other ?
mike


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## mesenteria (Oct 29, 2015)

Yes, but.....

The separation to get them close to parallel would almost certainly be insufficient for clearances. The cars and engines, especially steamers, are likely to make contact.

Now, if we were discussing this matter with 40" and 42" curves, it might be almost no problem at all to 'nest' the curves.


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## MichaelE (Mar 7, 2018)

Mine are parallel with 2-1/4" clearance all the way around except for a hidden part where i separated them a bit farther.

303mm passenger coaches barely pass each other. I hear contact every once in a while, but not enough to even rock either car.


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## bristolman2012 (Mar 4, 2012)

*steamers*

running nothing but diesel , no steamers if that makes a deference.


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## MichaelE (Mar 7, 2018)

The length of the equipment makes the difference.


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## DonR (Oct 18, 2012)

Two factors to keep in mind when running tracks
parallel on curves.

1. Long cars and locos on the outer curve will overhang
the ballast making them closer to the inner
track.

2. Long cars and locos on the inner curve will jut
out towards the outer track.

These two factors can result in crashes.

That is what Micheal was describing.

Don


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## Dennis461 (Jan 5, 2018)

If you have more room available, spread them out.
I am posting pics of my end of the line, two spur tracks.
22" inner radius
24.25 - 24.325 outer radius ( nobodys perfect).

I planned on all short cars and engines.
My brother gave me two heavyweight passenger cars and a cab forward .
Also, in the pics, the Atlas RS1 is a bit longer than an F7 or SW1500.

Also keep in mind, there is no room between tracks for signal lights, MOW tool boxes, or a cow!

First picture has an Atlas RS and a Mantua 4-6-2


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## mesenteria (Oct 29, 2015)

bristolman2012 said:


> running nothing but diesel , no steamers if that makes a deference.


It may, but it may not. This means it falls on you to make a verifiable determination. Mock it up on a part of drywall sheet or plywood, and run your longest items and shortest in combinations. The idea is to find the one item whose stirrups or pilot or window shades....something is going to make you go "D'Ooooohh!!!"

One other tip many don't know, or they forget: Reversing. When cars trail each other, they'll stay coupled on curves and they may not make contact with others beside them on nested curves. But back the engine and shove those same cars and watch what happens. Whole 'nuther ball of wax.


So, to summarize, the longer items may clash at their middles and ends if the curves are too close to each other. The middle of one car will swipe the end sill or stirrups or handrails at the ends of the others going past them. They may be fine when trailing, but when being shoved they are more likely to clash.


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## bristolman2012 (Mar 4, 2012)

*nice pictures ,*

thx for input . ill put track parallel and run 2 trains by one another and see what happens . ill lay 24 radius with ties to the line not centered .
mike


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## Bwells (Mar 30, 2014)

ill lay 24 radius with ties to the line not centered .

Okay but what does that mean? Two inch track spacing is too tight for a yard and should not be done on a curve. If you must, hold the pivot point for the 22 back 2" from the pivot point on the 24". You will still be 2 inches away when straight though.


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## 65446 (Sep 22, 2018)

Just in case you use flex track for curves, before bending any, lay 2 or 3 sections out straight somewhere convenient, add rail joiners and solder them together end to end. This ensures a really smooth curve with no kinks where they're joined, when you do bend them. If you don't already own one, buy a pair of Xuron Rail Nippers to trim off any excess rail sticking out too far to mate with an ensuing section of track..It's a very important tool for this hobby. When you do use them, the flat side of the jaws face the good rail, not the rail you're getting rid of..Finally: You cut from top of rail (railhead) to bottom of rail (foot), not from one side of the rail to the other..
Apologies if you already know all this...M, Los Angeles


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## mesenteria (Oct 29, 2015)

bristolman2012 said:


> thx for input . ill put track parallel and run 2 trains by one another and see what happens . ill lay 24 radius with ties to the line not centered .
> mike


Two nested curves can be on the same radius, but their centers of radius will have to be displaced by the distance between the centerlines. Also, the outer curve cannot have the same parallel extensions because two curves of the same radius that are nested will, because their centerlines are displaced, eventually interfere with each other. That is, they'll cross each other necessarily:


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## CTValleyRR (Jul 26, 2014)

telltale said:


> Just in case you use flex track for curves, before bending any lay 2 or 3 sections out straight somewhere convenient, add rail joiners and solder them together end to end. This ensures a really smooth curve with no kinks where they're joined, when you do bend them. If you don't already own one, buy a pair of Xuron Rail Nippers to trim off any excess rail sticking out too far to mate with an ensuing section of track..It's a very important tool for this hobby. When you do use them, the flat side of the jaws face the good rail, not the rail you're getting rid of..Finally: You cut from top of rail (railhead) to bottom of rail (foot), not from one side of the rail to the other..
> Apologies if you already know all this...M, Los Angeles


If you're using Atlas, Peco, Walthers, or any of several other brands of flex track, this is absolutely a must-do.

On the other hand, if you're using MicroEngineering, Hornby, or other "stiff" brands of flex track, you do not need to do this because the track stays where you put it, and there is only a kink if you bend the track incorrectly. I use a plastic radius template to make sure the curves are identical on both sides of the joint.

Also, I prefer to use a cutoff disc in a motor tool to cut my track. I think it makes a cleaner cut than nippers.


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## Bwells (Mar 30, 2014)

We all have our own preferences and I prefer the Xuron nippers for ease of use. A dremel works well and so does an Atlas razor saw and in a pinch a hacksaw with a real fine tooth. Anything handy will do the job so pick your tool and you will be fine.


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## MichaelE (Mar 7, 2018)

I love the Dremel too. I've never had or used a rail nipper, but it's something I might try down the road.

Those cut-off discs are very fragile and cannot take much lateral stress without shattering into several pieces.


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## 65446 (Sep 22, 2018)

CTVRR, I believe you're incorrect about stiff brands of flex.. Unless you are only needing to install 1 section of it, it's the same situ. You will never get a smooth or kink-less spiral [curve] unless you do the same; solder 2 or more tangents together first, before bending...Stiiff or not it's the same. An exception would be for a really funky bucolic class B or C branch, or 5Mph small yard..Here you might actually want the track kinked in lots of places and even be code 70 or 40..


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## CTValleyRR (Jul 26, 2014)

telltale said:


> CTVRR, I believe you're incorrect about stiff brands of flex.. Unless you are only needing to install 1 section of it, it's the same situ. You will never get a smooth or kink-less spiral [curve] unless you do the same; solder 2 or more tangents together first, before bending...Stiiff or not it's the same. An exception would be for a really funky bucolic class B or C branch, or 5Mph small yard..Here you might actually want the track kinked in lots of places and even be code 70 or 40..


Either have a lot of invisible kinks in my track that don't affect operations, or I'm not wrong. I'm betting it's the latter.

But I believe you missed the part about using a curve template to ensure you have a smooth, continuous curve through the joint. Yes, you can still solder the pieces when straight and form them afterwards, but you don't HAVE to.


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## bristolman2012 (Mar 4, 2012)

*coming out of switch*

doing the new layout , issues right now are the switches and connecting to a curve . if the rails don't quite meet do u try to even out ( some of my switches the ends aren't even ) ? also having tough time track keeping together till it's connected (nail and pull back up ) ?
mike


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## CTValleyRR (Jul 26, 2014)

bristolman2012 said:


> doing the new layout , issues right now are the switches and connecting to a curve . if the rails don't quite meet do u try to even out ( some of my switches the ends aren't even ) ? also having tough time track keeping together till it's connected (nail and pull back up ) ?
> mike


A lot going on here. When you say switches, I assume you're referring to turnouts, and not the electrical variety.

First of all, how are the turnout track ends not even? Did you or someone else cut them at some point?

Are you using flex track? If so, you can and should trim it to fit. Are the nails pulling out because the flex track wants to spring back straight? What is your roadbed and subroadbed made of that it won't hold nails? And as telltale and I discussed above, if you're using the springy-type flextrack, solder the pieces together while they are straight. That makes your end joints line up.


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## mesenteria (Oct 29, 2015)

bristolman2012 said:


> doing the new layout , issues right now are the switches and connecting to a curve . if the rails don't quite meet do u try to even out ( some of my switches the ends aren't even ) ? also having tough time track keeping together till it's connected (nail and pull back up ) ?
> mike


Flex track has a sliding rail because the radius of the two rails will be different when you bend them into a curve...but the length of neither rail changes. The idea is to trim off what protrudes, or better yet, slide the extended length into the spike-head details of the mated length of flex track. This strengthens the joint along the curve and helps to avoid kinks at the joint. Works for me, anyway.


The six rail ends of a 'switch'*, commonly called a 'turnout' by both the railroad engineering staff who design trackwork, and used most often by those in the hobby, should all be even across the pairs. If not, someone has customized your turnout...it's used. Where you are attempting to mate curved flex track to either of the three exits of a turnout, you really ought to do two things:

a. have close to a boxcar length of straight (tangent) rail before the joint. Approaching the points rails and the frog on a straight path is much better for preventing unwanted derailments; and

b. use track nails to fashion your curve and approach to the turnout, and mark the extended rail (the sliding rail should be on the inside of the curve if possible). Once you have the rail marked, remove one tie under the mark so that the joiners have room to slide, and carefully cut the rail using the proper nail cutting tool.

* a turnout does have a 'switch'. It's only the headblocks, throwbar, and the points rails themselves. A switch is therefore part of the greater appliance called the 'turnout' by the engineering departments. In modern days, entire turnout assemblies are built in a building and flatbedded out to the site for hoisting and installation.


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## Bwells (Mar 30, 2014)

I assume we are still talking about the Apex and Hypotenuse layout from your previous posts. If so here it is for others to see.










The turnouts are specified to be atlas mark 4 and should work provided you follow their design. I remember you enlarged the table so things may not work out as planned but this can be done with flex track but not sectional track. Can you post pictures yet as it would help alot as I think most of us have a hard time understanding what you are asking.


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## bristolman2012 (Mar 4, 2012)

*apex*

your right about not following , I did increase table width by a foot , and thought I would be able to have a 22 radius as the smallest . ( still trying to achieve that ) . as there is the 25 deg crossing I'm trying to use that as my starting point . I've pulled a lot of the small pcs back out and started using more flex . hopefully starting to learn a little as I go , only want to lay track one time and done . I am using track nails to hold things in place , not driving down though and that helps too . 
mike


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## Bwells (Mar 30, 2014)

The angle of the crossing maybe a little different since you enlarged the layout. Are you placing this on ply or foam? If ply use push pins. I still think you need to account for the grade on the up-and-over, it will be stiff. Are you using sectional and mark 4 turnouts or the snap track type?


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## bristolman2012 (Mar 4, 2012)

*thank you for interest and help bwells*

all code 100 atlas track ,# 4 atlas snap switches , 22 radius ,24 radius , ( have 18 radius but tying not to use ) , 3 boxes flex but have cut some already . 2 radius to the left on the layout was where I was trying to do 22 radius ( up ) and 24 radius on the outside one ( other what I call parking area I was going to use flex as far as I could go . on the 3 curves to the right 22r first, 24 second , and the third I could do a 28 r without going too close to edge. most of the material I got was from an old guy who said (he had sold all his old locos ) 50 bucks for the box . it had all code 100 Nickle silver , mixed straight ,curves and about 13 snap switches ( all worked by the way )and track nails ,switches ,wires ( not using though ) , toggle switches . for me not knowing a lot it was candy land . did a double loop layout with it . putting track down on ply right now and will use foam after sure track laying is good .
mike


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