Combining 27" curves and 42" curves

Maybe you mis-typed your 2nd option of "(2) a mix of 27" and 42" curves where I'd go 42-27-42-27".  Two of the 42s with the two 27s would leave you 30 degrees short.

Your final comment with the extra 42 at the end would work well.  I do it all the time.

There was a forum poster who used to describe this all the time  I haven't seen him post in a while, but below is a link to a search where Ace describes this  take a look through these  

https://ogrforum.ogaugerr.com/a...agination.sort=SCORE

JD

I have found that the different curve sizes in 027 can make it difficult to make a half circle or partial circle, may need some half track curve sections or have to cut the curved track to fit. If you stay with one size curve it is much easier to work with.

I have used 027 half curves to work with engines that need a higher radius curve; one half curve track then one half straight and again a half curve, repeat it through out the curved area.

Lee Fritz

You are on the verge of creating a spiral easement:  042-027-027-042 approximates the way real RRs make curves by easing into them.  The whole thing looks much more natural than a plain straight-to-curve, even if the plain curve is of a larger diameter (and I wish I had room for easements).

That said, there is nothing operationally wrong with the 034, either.

I wouldnt alternate radii (42, 27, 42, 27 ....) , i would lump all the 27s in the middle as suggested above. 

Other alternatives would be Gargraves 032 or Ross 031, both of which are the same height as O27 track, just use the transition pins.

You could use the Marx 034 as well.

Any of those are, IMO better options because then you're not limited to O27 trains.

Last alternative is to just buy gargraves flex and bend it around something to make whatever radius best fits the space. 

Just to clarify what Walt referred to about degrees of curvature.

To make an end loop you are turning 180 degrees. When combining different diameter curves, all have to add up to that 180 degrees to make a smooth curve.

The amount you turn in degrees for each full track section depends on the number of sections that make up a circle in that diameter. It doesn't really depend on the diameter itself, just the number of sections that make a circle

For example, if 8 sections of track make a circle then each piece is 45 degrees and each half-section is 22.5 degrees

12 sections to a circle ----> each piece is 30 degrees and each half is 15 degrees.

16 sections to a circle ------> each piece is 22.5 degrees and each half is 11.25 degrees

If your curves don't add up to exactly 180 for each half circle, you will not have a complete half circle and smooth curves. That is why you often end up cutting track when making hybrid curves. Luckily (or maybe by design!) even with all the different diameter curves available, most fall into 8, 12 or 16 per circle, simplifying things for the layout builder.

Also, remember that if an engine is rated at a certain curvature, even one piece of track with a curve tighter than that might cause problems. Just as "a chain is only as strong as its weakest link", so, too, to an engine going around a loop, "a curve is only as wide as its tightest curve section".

Jim

I have found over my many years of assumed mistakes  that any turn around is always smoother when one radius track is used and the largest one possible at that is always best.

walt rapp posted:

Maybe you mis-typed your 2nd option of "(2) a mix of 27" and 42" curves where I'd go 42-27-42-27".  Two of the 42s with the two 27s would leave you 30 degrees short.

Your final comment with the extra 42 at the end would work well.  I do it all the time.

Yeah, I left out a 42 in the first....I often think faster than I can type.

Agree with Jim's comment above that I'd be limited to engines rated for 27" curves (chain as good as the weakest link) but I think I can live with that.  Most of my engines are rated for 27" with a few rated for 31", nothing bigger than that. My 31" min. curve engines are ones I'd rather not put on an elevated level for fear of breakage. Thinking I'd run a few cheaper ones on the elevated level that, if they tumbled, I wouldn't lose a lot of sleep or value.

I combined different curves like that wih Standard and O guge but as I have up graded my layout track I have eliminated them. The trains don't look right going through such a curve. Especially a tight curve-they  whip  through the curve and not a very prototypical action. But if you need it to complete your trackage-do it.

Hey it will work! My layout is all O27 track but the main loop has no 27" curves, the smaller loops do. The outer main loop does have a big mix of Lionel O42, O54, and K-line O72 with a 1/2 circle of Marx O34. Works fine, Don't be afraid. Nice thing about using the smaller curves is it will keep you from wasting $$$$$$$$$$$$ on stock that needs wider curves. The neat thing about tubular track is you can cut and fit it to anything you like. Try that with Fastrack.

Check my Youtube site for a look see.

For me,,,prototypical is overrated. JMHO

KRM posted:

Hey it will work! My layout is all O27 track but the main loop has no 27" curves, the smaller loops do. The outer main loop does have a big mix of Lionel O42, O54, and K-line O72 with a 1/2 circle of Marx O34. Works fine, Don't be afraid. Nice thing about using the smaller curves is it will keep you from wasting $$$$$$$$$$$$ on stock that needs wider curves. The neat thing about tubular track is you can cut and fit it to anything you like. Try that with Fastrack.

Check my Youtube site for a look see.

For me,,,prototypical is overrated. JMHO

Watched your video. Great job on the layout. Not all the detail of a scale, but terrific toy train layout. 

I wish I had that much space, but I lost my battle for basement space. Had to tear it down and move up into a spare bedroom and am limited to 8'x11'.  I've got 54" curves on the outside loop and 42" and 34" in the inner loop.  Had to go with basic loops around my operating yards.  For the elevated, though, I want a more interesting circuit, but can't avoid using some 27" curves to accomplish what I want to do.

FWIW, some rolling stock and locos that nominally require larger radii WILL work with 027 IF they are eased into it with the larger curves.

You have the right combination of degrees with 3 -O42 and 2-O27. Just cut an O42 by measuring 5.5" from rail end to rail end of the outside rail to create an O42 1/2 curve.

Then, the combo is O42>O42-1/2>O27>027>O42-1/2>O42

          30°>15°>45°>45°>15°>30° = 180°

It is about 31.5"-32" outside rail to outside rail wide.

here it is compared to the alternating proposal that you have:

Both may work, but the wiggling of the alternating pattern may cause strange behavior of the trains.

Moonman posted:

You have the right combination of degrees with 3 -O42 and 2-O27. Just cut an O42 by measuring 5.5" from rail end to rail end of the outside rail to create an O42 1/2 curve.

Then, the combo is O42>O42-1/2>O27>027>O42-1/2>O42

          30°>15°>45°>45°>15°>30° = 180°

It is about 31.5"-32" outside rail to outside rail wide.

here it is compared to the alternating proposal that you have:

Both may work, but the wiggling of the alternating pattern may cause strange behavior of the trains.

 

Great idea. Thanks.

Just to throw something else out there, Menards offers O36 curves in track that matches the profile of traditional O track.  While not a match to O27 profile, it looks fairly similar.  With some finagling you can get traditional O and O27 to match up fairly well as well.  

JGL

If you have the track handy, why don't you just put it together and see if you like it.  It's five or six pieces of track.  Would probably take less than five minutes (two?) to put together then run some cars around it.  That is the only way to know if you like it anyhow.  This thread has been going on for three days.

You can always put a straight to fit in the middle to widen the diameter as well.  O27 with a nine inch straight equals 36".  I think it does anyway.

Chiming back in: I agree with GG1MAN's comment about consistency in the curve diameters.  42-27-42-27-42 does work and I actually did that one year on my Christmas layout only to tear it out and redesign the u-turn.  The train sort of "jerks" around the curve if you can picture that.  Not because of mechanical constraints but because is glides thru a nice 42" curve and then changes course thru the 27 making a sharper turn, etc.

- walt

Thanks Walt.  I'm going to try the other suggestion of 42-1/2 42-27-27-1/2 42-42 rather than 42-27-42-27-42.  I think that the 42s will ease the train into the 27s.

This is strictly with an elevated level.  I'm using 42" and 54" on the main level except for a few spots in the yard where I used a few 27s.

If I did my quick arithmetic (with pencil and paper - old school!) correctly, you will have invented 0-37 track curves, or re-invented flextrack of a particularly chunky nature.

raising4daughters posted:

 

Watched your video. Great job on the layout. Not all the detail of a scale, but terrific toy train layout. 

 

Thanks,

The main engineer other than me is three so it works as a toy train layout for us. I have my sections and he has his.   I have found that detail of a scale layout and a three year old don't mix to well. Same with it and a cat.

KRM posted:

raising4daughters posted:

 

Watched your video. Great job on the layout. Not all the detail of a scale, but terrific toy train layout. 

 

Thanks,

The main engineer other than me is three so it works as a toy train layout for us. I have my sections and he has his.   I have found that detail of a scale layout and a three year old don't mix to well. Same with it and a cat.

I don't have the artistic skills or time for a detailed, scale layout with scenery. Maybe some day in our post-children home after retirement. Right now, I'm going for the fun aspects. My youngest is 9, others are out of the house (19,22,23), so it's mainly just her and me, but figure grandchildren will be coming next 5-10 years.

I've got my around-the-ceiling layout running and am working on the main level. Track is laid and started wiring today. Just can't seem to string enough hours together without interruption.  Hope to build an elevated level on it, too, but want the table-top usable first.