So if I have 6- 18" curved track with a 9: in the middle would it be a 27" diameter. ??? Just one of those questions that has been bugging me… much more to follow LOL Joseph
would that be 6x18/ 9 = 27?
well let see I have 6 each of the 18" curved track with a 9" in the middle on the ends of a 4x8 ho layout
a half circle of 18" radius with a 9" straight in the middle would give you an overall diameter of 36" + 9", or 45". And just barely fit on a 4x8. That would be a bit close to the edge for my tastes.
–Randy
jlcjrbal: That 18" track is 18" RADIUS, not diameter. Thus a half-circle of 18" track is 36" wide, center-to-center. It is still 18" radius track no matter how many straight pieces you put in the middle–but if you have a half-circle of 18" track with a 9" straight in the middle, as rrinker menitoned, it will be a total of 45" wide.
Thnaks for the info… Sometimes it is easier to ask a simple question here then keep me up late at night staring at my layout… Joseph
The radius, no matter what it is, stays the same no matter how many pieces of straight track you insert. Think of it as so many degrees of your radius, then a straight section, then so many (same or different) degrees of the radius, etc.
It’s not as mind boggling as it may seem. This concept was presented to me when I was a kid reading some track plan article some place. The author said to cut a certain radius to so many degrees for a filler piece on a curve . . . Whaa…??? Well luckily, the track plan was for sectional track, so I had a visual aid to go by, and somehow I finally “got it”.
Here’s an example that might help illustrate. Think of your snap track curved sections (whatever radius they are as it doesn’t matter to illustrate the concept), and put them all together to create a full circle. That would equal 360 degrees. Make it a semi-circle, and you’ve got 180 degrees…but it’s the same radius, though. Remove a couple more sections of snap track until you have a quarter circle. Now it’s STILL the same radius but it’s now at 90 degrees…and so on. Get it?
If you were measuring this with a protractor, the zero point of it would be set at the same center point you would use if you were drawing out the radius by hand (to the center of the track). So on the track plan I mentioned earlier, I would use the protractor to mark off that angle and then extend it out on the table top until it crossed the track centerline, and this is where you would make your cut. Clear as mud, eh?!
Well anyway, it’s a useful concept that you just might have use for someday on a future layout or hand drawn trackplan.