I am new to the hobby and am planning a layout. Not great at math or geometry - so is there a trick to drawing and joining smooth curves on paper and on the layout?
I have a circle template, but find it hard to make the correct placement in joining the circles depending on the radius of the curve, etc.
Surely there must be a simple way I am unaware of!
Thanks for any help you can provide!
Do you mean like including easements so the track makes a gentle transition from straight to curves?
when you look at the pre-cad layout design books by John Armstrong which describe using circle templates as well as easements, he starts with the curves and then connects them with tangents. There can be small bends (curves) between the larger curves where track loops back on itself.
It sounds like you may be looking for a french curve. Amazon is one source.
https://en.wikipedia.org/wiki/French_curve
CG
I am a civil engineer. I have been using AutoCAD since the mid-eighties. Before that I was a draftsman. I sat at a very large table on a high stool and had a variety of drawing tools to lay out curves of all sizes. Smaller curves were drawn using a compass or a circle template. Larger curves (and I mean curves with radaii such as 10" or 100" or 200" or 5000") were drawn using templates like this:
http://www.smithdrafting.com/2003.jpg
In a forum like this it would be difficult to exlain just how to use such things, but maybe some patient and detail-oriented member can put together a drawing primer.
Hope this helps, or at least gets you started and points you in the right direction.
Robert
You can use a simple straight piece of wood like a yard stick to draw even radius curves. Drill a hole for the pivot point and then drill holes at the appropriate radii. Pin or nail the pivot point loosely at the center of the circle the curve would form if it went 360 degrees, and then draw the curve at the chosen distance from the center.
Better still, draw easements at the start and end of the curve. An easement is a type of curve that gradually gets tighter towards the centre and then gradually gets bigger towards the other end. The advantage to them is that your trains are not thrown dramatically into a curve as is the case if the track goes from being straight directly into the fixed radius of the curve. The easement makes the motion of the train look less toy like and it is less prone to derailments.
The downside to an easement is that the center of the curve can get too tight. You have to have a reasonable amount of space to use an easement.
If you haven’t already got a copy, I recommend getting your hands on a copy of John Armstrong’s ‘Track Planning for Realistic Operation’. It is a wealth of information about how to avoid making mistakes when planning your railroad, and it shows in detail how to draw a curve with easements using a trammel stick.
https://kalmbachhobbystore.com/product/book/12148
You can also draw easements with a long, thin, flexible strip of wood. When bent, the wood will naturally form easements. You need a couple of nails to anchor the strip at the beginning and end of the curve and then you just slide the strip between the nails to get the curve you want. Put a nail in the center of the curve to hold it and then get out your pencil.
Dave
I spent way too much time in public school doing this. I wish they taught me how to run a lathe or how to weld. Not once in the 55 years since have I had to crank out an orthographic projection.
Ditto on the comments on the Armstrong book.
So did I, but drafting class was my favorite. It was easy as pie and was completely second nature to me. Then there was the matter of Ms Morton’s algebra class and Mr White’s geometry class . . . and then the formidable Mr Tomczck’s calculus class. He was Polish and dint speak da English too good. But still, all useful endeavors that make laying flex track on plywood accurately a breeze.
Robert
I think Dave nailed it with using a yardstick as a compass. That has worked for me since my first layout back in the mid 60s. When I started my current layout in 1988 I bought an aluminum yardstick and starting at the 36” end drilled a 1/16” hole in the center of the ruler every ½” stopping at 18”. Next I slightly tapered the holes on one side so that a pencil will easily mark the working surface.
As nails sticking out of anything can really ding a klutz like me I use small wood screws or a scratch awl for the pivot point. A small wood screw won’t punch a hole in me like a nail.
It helps me a lot to label each pivot point with a pencil for future reference. Comes in handy for adding a parallel track later.
You will have to come up with workarounds for some curves but that will come with experience.
Yes, but sometimes the radius point is inaccessible, making it impossible to sweep an arc. It might be in a solid wall or hovering over an open aisle and there is no place to stick the pivot nail.
I lay out curves from the tangents. I have not read the Armstrong book (blasphemy, I know!). Apparently he advocates laying out the curve first and then adding the tangents. I do it exactly opposite. A little more math involved, but no big deal.
Robert
You left out my bottom line [;)]
“You will have to come up with workarounds for some curves but that will come with experience.”
Mel
Modeling the early to mid 1950s SP in HO scale since 1951
My Model Railroad
http://melvineperry.blogspot.com/
Bakersfield, California
I’m beginning to realize that aging is not for wimps.
There were also some good suggestions on the topic in this older thread in which you participated
http://cs.trains.com/mrr/f/11/t/226176.aspx
It might help others help you if you described your situation a little more so that folks can know where you are having trouble.
That’s right Mel, but I certainly didn’t ignore it or intend to change the meaning of your post. I was trying to explain how I work around one of those special cases you described. It just so happens I use that tangent technique for regular cases as well.
I always try to trim posts and quotes and whatnot for clarity and to save space. Plus, I am responding using my cellphone and the little editing window is pretty dang small and my fat thumbs are pretty dang big.[tup]
Robert
You don’t have to explain the fat finger thing, I have that problem on LARGE keyboards. And that wasn’t a gig from me either, all in fun.
As a long time CAD (about 29 years) freak I’ve pretty much tried every thing at lest once, a full size plotter would take care of almost all layouts. I’ve pieced 11” x 17” printouts together for larger drawings more times than I would like to remember but it works best for me. The yardstick is a bunch cheaper than a 48" plotter.
I was very fortunate to have a 42” plotter in my office until I retired, that spoiled me rotten. Now I’m stuck with an HP 4V, max print is 11” 17” with affordable paper at $22 per ream. 13” x 19” paper is 20¢ per sheet.
I use a piece of wood instead of a yardstick - used to get yardsticks by the ton for free from local hardware stores and stuff but not so much these days, so I just measure and drill holes in a piece of 1x2. For curves where the center is off the layout, a photo tripod handles the pivot point.
–Randy
Thanks everyone. I can draw the circles/curves, but connecting the circles/curves (for example in creating a smooth “S” curve from two joined circles) is where I am having the difficulty.
Easements are most certainly another concern, and since I plan on having open benchwork, I won’t have as much room for adjustments when the actual track laying begins.
I’ve read that in using flextrack, a natural easment can be created AS the track is laid, but with open benchwork, I need to be more precise with the roadbed as I won’t have as much room for adjustments when actually laying the track.
Which brings up another question. If I am following a drawn line when laying my track, how do I plan for a “natural” easement if I don’t know it until I actually lay the flex track?
With sectional track, you pretty much know where is goes, but with flextrack, it would seem I could be off a couple of inches when laying multiple curves.
Does that make sense? Thank you!
Back when I first got interested in this great hobby the guys here helped me to come up with a layout plan and I did it on paper, when I went to lay the track which is what I did before putting doen the roadbed ( cork ) , I had found the drawing to be more of a rough guide but because I was using flex track I found the flex track curves would find their natural curve and didn’t like being forced.I have since learned to use xtrackcad to design my track plan , it is precise as it needs to be unless your using a solid top, I use open grid with risers and 3/4" plywood cut wide enough for the roadbed to mount on plus I’ve learned its better to give 1/4 - 1/2" on eachside for attaching scenery. If you are not in a rush I would recommend learning a trackplan software, if not for this layout perhaps the next, there will be a next.
Perhaps you can scan and post your plan for the guys to help you out?
steve
If you draw a line from the center point of one curve to the center point of the reverse curve, then both curves (even if they have different radii) will meet exactly on that line and produce a “smooth S curve”. But you don’t want a smooth S curve, you want to have a straight tangent of at least one car length between the reverse curves.
Robert
THANK YOU! I think I have the answers I need as I PLAN my layout on paper. I suppose I really need to buck up on track planning software. Having checked out the sample “try before you buy” tutorials, I was a little overwhelmed - plus, I still like a larger paper drawing, though I know it isn’t necessary.