I’ve searched and found only limited information and could use some help. My last layout was built with HO Scale Unitrack and I never had to worry about working with flextrack and getting curve radii corect. Now that I’m building version II I have curves of various radius such as 26R, 28R and 30 inches. I have no idea how to figure out the centers, how to make a tramell, etc. Can anyone point me in the right direction? Even for a geometry trainwreck such as myself, this can’t be that hard??? Or is it… [:(][?]
I built a large compass out of scrap wood with a nail and 2 pencils. I then drew templates in my radii on scrap masonite and cut 1/4 circles out on my band saw. I then used those templates to help lay track. It worked very nicely.
Thanks guys, but how did you know what to do to get the correct radius? I’d like to draw the correct curve radius right onto my foamboard layout top if possible…
Maybe this will help, Radius is half of a circle, or diamater if you will. So if you want a 24" radius curve take a string for instance, that measures 24" and place one end at a stationary point. Now, make a big circle with it, the curve that is made will be the radius of your turn…I hope this doesn’t confuse you, its rather hard to explain in writing.
I’d sure like to have some good curves back, but every time that Christmas comes…oh, wait, you were talking about something else…? [:I]
This is where a computer or graph paper and scaling a workable plan become so important. Everything has to fit because at some point, you have to close the big loop. Ideally, that should not be with a jink…or what we know as an S-curve.
I’ll tell you what I did; I used masking tape to mark the track, including curves and turnouts, and when that all seemed good, I used either snap track or flex to generate the footprint that I had planned.
You will never get it all 100% right, or as a match to your Master Plan. At some point, you will be out by as much as a whole inch, but the error should be in length, not in radius, that is, having a left rail meet a right at the closure point.
Mark it out with tape, and then lay the curves that you mark using flex-track. Continue moving out from the curves, alternating between the left and right sides of the curve, until you come to a point where your first turnout is to be placed. Place it properly, and then continue past it, on both sides of that initial curve remember, and eventually you will have to make the ends meet. You can adjust the last bit of straight and the last couple of curves a bit, and make the ends come together nicely.
I may not have addressed your actual question…sorry. Determine the minimum curvature for the rolling stock and the largest locomotive that you are ever going to want to run on this layout…try to predict if you will expand your stock. Then, lay out those curves where you want them, and use the masking tape to mark near their centers. When you have your desired curves placed, then make tape straights between them, and mark the turnouts with a diverging piece of tape.
So, you find a piece of wood or dowel, mark inches on it with a marker, starting with one end that will be your pivot point. Then, place the pivot anywhere that seems reasonable (guess) and sweep the other end around in an arc. Note where the inches of radius marker sweeps, and mark that with a few swipes of the marker. Then, move to another spot. Keep doing this for all curves, and then use some coloured pins or something to mark the straights. Stand back and have a look from higher and from afar. Does it all look like what you want? If no, move the pivot points around and see how the curves change. Soon, you will have it the way you want it. Mark the PIVOT POINT this time, and you have that critical bit of information.
Selector brings up a good point. I am going to us code 80 flex track on my N scale layout and want to have 21" radius curves, so the easiest way for ME to do this is to buy a pack of code 55 section track is that radius and map it out on the layout.
It’s way easier than mentioned here. Go to Home depot or your local home improvement store and buy a $2.00 wooden yard stick. You also need a few finish nails. Take these home and using a drill clip the head off one of the finish nails and then chuck it in your drill. Using this drill a hole over the top of each number on your yardstick. Now all you have to do is go back and enlarge the holes over all the numbers EXCEPT the 1 inch mark. drill these holes to the size a pencil will fit into snugly. Now using a finish nail with a head on it in the 1 inch hole makes your pivot point. Just add an inch and the pencil goes into that hole and you turn your circle. So for a 24" radius you put the finish nail in the 1inch hole and the pencil in the 25" hole. Its easy and cheap to boot.
I’d liker to suggest something completely different. Take the time to learn a good track planning program (I like XtrkCad – it’s free). Design your layout there… the software will help you calculate and create appropriate radii. When you have a plan you like, print it 1:1 and lay it on your foam to create the lines.
I’m with toolbox_guy. The cheap wooden yardstick from the paint department at Home Depot has served me well. That and a few pencils. I did make a template from a sheet of styrene for easements.
The yardstick method works well, provided you have some place to anchor the yardstick., which on a narrow shelf layout is rare. That’s why I prefer the templates. I’ve also found it easier to try several different curves, before deciding on the right one.
Assuming you’re going to use roadbed, you might want to check out Ribbonrail roadbed. It’s made of upsom board, pre-cut in curves from 15" to 48" radius. All you have to do is lay out the roadbed in the track pattern you want, attach it to your base (I prefer small nails, some use glue) and then lay your flextrack on top of the roadbed. All you have to do is keep the track on the roadbed, and you know the curve is correct.[:)]
Since you seem to know the radii of your curves, finding the center point is not all that difficult.
With a black pencil, draw a straight line to represent the center-line of your straight track just before it enters the curve;
On that line, locate and mark the exact position where the curve will begin;
At that mark, draw a 2nd line in red, perpendicular (90° or at right angles) to your track, towards the inside of the curve – this is the radius line;
Measure from your track’s centreline (the black line), along the radius line (the red one) the desired radius of your curve, and mark its location – the center-point of your curve.
Using a method of your choice (such as the “yard stick” or the “sting” methods described in other posts), draw the curve using the center-point you just located in Step 4 as the pivot;
Now you have the center-line of your curve.
NOTE : This method does not incorporate any easements. It also requires that you have a place large enough to draw the lines you need.