curves vs curves with straights

I've done it lots of time in O gauge with traditional tubular track, Fastrack, and Atlas, and in  other scales, too. 

As to distance between track, I'd the center to center distance at least five inches and personally I strive for six. 

You can also mix and match curve sections in a curve to make adjustments.  You can sub in some larger diameter curves at the beginning and end of the curve and use tighter radius curves near the center.  This is what the real railroads do, they use a "spiral easement".  This type of curve makes it easier for the train to transition from straight to curve and vice versa.

Excellent suggestion.  Looks cool too. 

Thanks, i'm running gp20 and 38's right now with 3 1/2 between center on the straight aways with plenty of clearence but the turns are a different animal. I have a bent dog bone (2walls) 38 feet one way, 38 back around and a total of 3 different tracks one inside the other. Trying to run 3 engines at the same time but also trying to save space.

Are you running command or conventional?

I recently struggled with something similar.  I wanted to place a Fastrack 36" oval inside a Fastrack 48" oval, but didn't have room on 4x8 plywood for the 48" curve.

I used 36" curves for both loops with several shorter straight pieces in the outer loop--frankly, I'm a bit disappointed with the look.  The larger loop obviously doesn't maintain a consistent distance from the inner loop, and longer locomotives and stock look weird when they hit the curve, then a straight, then a curve again.

Would be less noticable on a higher radius curve, of course.  And it looks like you have far greater space to play with, which is certainy an advantage.

There is no nice "formula" for track clearance in curves.  The location of the boggie to the car ends will affect the clearance.  About the best you can do is set up a test where you run the worst case cars/loco's through the curves and note the overhang/underhang and the adjust the spacing based on that.  Minimum clearance figures on the trains are what is the tightest radius the object will handle without binding up.  The Williams scale GG-1 is just about 20 inches long.  It can navigate an O-42 curve.   It will also take out anything within 4 1/2" of the track on either side while doing it.

Running conventional with Williams and Lionel gp38's and a lionel gp20. Which is better conventional or command. New to O, did ho for years and wish i started in O to begin with but better late than never. Finding out that O is alot different than ho especailly with power issues. looking into a MTH 4-8-0, my wife loves those with all the sound and steam.

Another vote for using larger radius curves to ease in and out of corners.

I do it on my Layout and it does help. O-72 to O-54 to O-36 and back in one place.

Drawback to this is the extra space it requires. Not gonna fit on a sheet of plywood in most cases.

Gap between tracks is best tested with the equipment you plan on running. Big engines and long passenger cars are your likely suspects.

Put the engine on the inner curve and roll the passenger car past on the outer, keep at least a 1/4 inch gap as they will wobble a bit when running .

Your constraints are 4 foot width layout and FasTrack, and particularly, you can't fit a 180 degree turn of O48 FasTrack.

My suggestion here is opposite of an easements into a curve that has been mentioned above.

From the straight you can turn 45 degrees with one O36, followed by 90 degrees with 3 O48 curves, and then finish with another O36.

This fits on your 4'x8' board.  It looks better than the short straight.  The inner loop doesn't follow the outer curve perfectly, but it does look pretty good.

  --Joe

"

My suggestion here is opposite of an easements into a curve that has been mentioned above.

From the straight you can turn 45 degrees with one O36, followed by 90 degrees with 3 O48 curves, and then finish with another O36."

this is my thought also.. I haven't been to my layout in a few weeks. but I am thinking

of testing out...

1/2 O36; O48; 1/2 O36; O48; 1/2 O36; O48; 1/2 O36 .

my internal loop will be O31 when it gets here..

Arrgghh, blush.  I messed up ( not used to the O31 FasTrack in the RRTrack menu).  The above image shows O31 FT mixed with O48.

This image is what I claimed the above.  It is comes close to the edge:

..

..

This is the mix that was suggested by bptBill.  The outer loop here is very close to the the inner loop.

Wanted to pop back into this thread to offer my thanks to Rail Reading.

Two pieces of 036 & three pieces of 048 on the outer loop gave me just what I was looking for, and I've made the changes on my layout.

This forum continues to be a place for sound insights, particularly for novices like myself.  Thank you!