N scale S curve on layout plan?

[CBQ Fan]

Ok, I am going to try and explain this section of my potential track plan. Double line main track makes a 90 degree 24” radius turn to the right.  The turn will straighten out for 2’. It will then make 90 degree 24” radius turn to the left.  Another 3 or 4 feet straight track followed by a 90 degree 24” radius turn to the left.  Would there be any concern about long trains going through the S curve. All of my past layouts have always had left hand turns so I have never run across the opportunity for an S curve like this. I have a mix of coupler mount and body mount cars. Sorry I have no track diagrams to show. I appreciate any insight.

[Santa Fe Guy]

IMO as long as you have straight track over a good length between each set of curves you should be okay.
 Consider putting in a good transition into each curve like the NMRA recommend so the trucks have time to settle into their rightful position.
Long cars especially pass cars will thank you for it.
Rod.

[ednadolski]

"Long trains"  == 30 cars?  50?  more?   Any grades?

The 24" radius curvature is a plus.  Mixing body- and truck- mounted couplers could be a concern; another factor is mixing cars with substantially differing overhang.  As @Santa Fe Guy says, sections of tangent track and easements will help.

Ed

[MVW]

IMO as long as you have straight track over a good length between each set of curves you should be okay.
 Consider putting in a good transition into each curve like the NMRA recommend so the trucks have time to settle into their rightful position.
Long cars especially pass cars will thank you for it.
Rod.

Yep, transition curves, and tangents at least as long as your longest cars (or motive power wheelbase) between opposing curves should serve you well.

Jim

[nkalanaga]

I'll agree with the transition curves.  With two feet of straight track, you can easily use 12-inch long transitions at both ends, and still have close to 12 inches of straight track.  The key is that, normally, half the length of the transition is in what was the circular curve, and have in the straight between them.

Note that, to keep the curve centers and radii the same, the straight section between the transitions will NOT be on the original alignment.  The transitions will have to start a little earlier, and the straight will be at a slight angle, in order to keep the original curve locations.

If you have printed transition templates, showing where they meet straight and various radii track, you can splice together a combination template, and play with it to get the exact alignment you need.

Another trick is an "artist's spline", a long length of flexible wood, for drawing smooth curves.  You can pin both ends along the curves, and allow the middle to adopt a natural transition between them - that's what it's for.  For this, you'll need one about six feet long.  A length of any flexible, springy material will do, as long as it curves, rather than kinks, when bent.  Two pieces of code 80, or heavier, rail, soldered together, might work.

[CBQ Fan]

"Long trains"  == 30 cars?  50?  more?   Any grades?

The 24" radius curvature is a plus.  Mixing body- and truck- mounted couplers could be a concern; another factor is mixing cars with substantially differing overhang.  As @Santa Fe Guy says, sections of tangent track and easements will help.

Ed

40 cars or less on freight trains.  I model 50’s & 60’s primarily so the freight cars are shorter.  Passenger trains up to 16-20 cars.  No grades.  I use the scenery to change the height of the terrain. 

[CBQ Fan]

Thank you all for your insight and information.  It is very helpful.

[ednadolski]

40 cars or less on freight trains.  I model 50’s & 60’s primarily so the freight cars are shorter.  Passenger trains up to 16-20 cars.  No grades.

Sounds like you should be just fine with those geometries.

Ed

[CBQ Fan]

That is good to know!  Thank you.