I have my latest trackplan drawn up 1" square graph paper. Some guys say to use a trammel and scribe the centerline directly on the plywood. So for this method, in the case of my trackplan, which is a 10 x 12 around the wall donut (continuous run) I would need to use a tripod to act as a center point in order to swing my arcs. In order to achieve a 3" wide subroadbed “strip” I would need 3 lead pencils inserted on the trammel, 1 lead point being the centerline itself, and the other 2 lead points would be 1 1/2" from centerline to provide my “cut lines” on the plywood to achieve the strip width of 3". I realize that I will have to hand draw the places where my turnouts are located.
The trammel I would make would support all of the radii used on the layout. With this method, since my layout is 2 feet deep on three walls, and 2 1/2 feet deep on the side that doesn’t have a wall (I made it wider because I will be able to access it from both sides, I would cover the benchwork by laying the 1/2" plywood flat and start the arcing.
To me, this method gets tricky because of the easements. Straight sections would have to be sketched to form the easements, so I would be erasing and redrawing on my plywood. And with all three lines being drawn at once, I think it could become confusing.
Here’s the plan:
Sorry for the wordy explanation, but I am hoping some of the plywood subroadbed pros could give me some advice before I go at it. My benchwork is staring at me and pleading for some risers and subroadbed! BTW, I have tried foam in the past and prefer plywood, and I have read most of the foam users arguments, but I guess I am from the old school and like wood. In any case,
I have my latest trackplan drawn up 1" square graph paper. Some guys say to use a trammel and scribe the centerline directly on the plywood. So for this method, in the case of my trackplan, which is a 10 x 12 around the wall donut (continuous run) I would need to use a tripod to act as a center point in order to swing my arcs. In order to achieve a 3" wide subroadbed “strip” I would need 3 lead pencils inserted on the trammel, 1 lead point being the centerline itself, and the other 2 lead points would be 1 1/2" from centerline to provide my “cut lines” on the plywood to achieve the strip width of 3". I realize that I will have to hand draw the places where my turnouts are located.
The trammel I would make would support all of the radii used on the layout. With this method, since my layout is 2 feet deep on three walls, and 2 1/2 feet deep on the side that doesn’t have a wall (I made it wider because I will be able to access it from both sides, I would cover the benchwork by laying the 1/2" plywood flat and start the arcing.
To me, this method gets tricky because of the easements. Straight sections would have to be sketched to form the easements, so I would be erasing and redrawing on my plywood. And with all three lines being drawn at once, I think it could become confusing.
Here’s the plan:
Sorry for the wordy explanation, but I am hoping some of the plywood subroadbed pros could give me some advice before I go at it. My benchwork is staring at me and pleading for some risers and subroadbed! BTW, I have tried foam in the past and prefer plywood, and I have read most of the foam users arguments, but I guess I am from the old school and lik
Or get a large peice of cardboard or poster board and use your trammel to draw a center line and 2 outside edges on the cardboard, cut them out and use them like a template.
Or draw the centerline radii on the carboard and cut it out to form centerline templates, draw the center lines, then measure out 1.5 in every so often and freeform connect those to make the cut lines for the plywood.
Or use the grid pattern to locate your centerlines and measure out 1.5 in on either side , draw lines to connect them and cut on those lines.
Useful variant: cut the template (carefully!) along the track centerline, then you can slide one side, draw lines on ply, slide the other side—.
See above
Make an easement template of posterboard by swinging a centerline curve, marking a tangent line (pick distance and unit of choice) outside the curve, marking the close approach half way from curve to tangent, then measuring 20-25 times the distance between curve and tangent along the tangent and as an arc along the curve. This gives you the three points necessary to draw a ‘close enough’ spiral easement. (I personally use a 10mm offset, curve radius 610mm - 24 inches - and measure 240mm to find the points of actual curvature and actual tangency.)
Given the chance, Atlas code 100 flex will form a proper easement if you pin it right at the first mark (halfway from curve to tangent) and bend it smoothly to meet the centerline of the tangent and curve where you marked the ends of the easement. Then, mark where the tie ends are. That way you can lay full lengths of flex and put the rail joints wherever the rails happen to end.
I use posterboard to establish my track configuration, cut it along the tie lines, spray it ballast grey and lay it on the foam with caulk. Then I lay the track right on it, with more latex caulk. Use up a lot of posterboa
Jigs work best. I bought a sheet of laun plywood (very thin approx 1/8 thick) drilled a 1/8 hole in a yard stick and notched my various radius I wanted to use, to accept a carpeners pencil, used an ice pick in radius hole and scribed my center lines on the ply. Cut out with a jig saw outside the lines and sanded back (electric sander) to the radius lines making a very nice smooth curve. Each jig will have two perfect radius curves and will last a lifetime. Just my two cents…John
Recently, I used 3rd Planit track design software to design my new layout. My approach, which I have described in this article, is to print out the track diagram 1:1, cut it out and stick it on the plywood and lay the cork and track directly on the paper itself. I found that this method works very well and there are no problems with the track moving provided of course that the paper is stuck properly on to the plywood.
Thank you for your kind words. I took another look at your track diagram and it seems to me that you could really benefit from using a track design program to help you get the flowing curves and easements that you like. I too like to use a lot of shallow curves in my design. When it comes to complex things like easements and grade calculations, I am quite happy to entrust that to the software.
The downside is that programs like 3rd Planit are definitely not easy to learn to use effectively. Even though I have an engineering and computer science background, it still took me a long time to figure out how to join two pieces of track smoothly in 3rd Planit. I wish they would produce a video to accompany the program.
Offset your straight mainline by an inch or so from the curve you’ve drawn with your trammel. Connect the straight to the curve some distance along the curve and you have an instant easement.
E.g. draw a 22-inch radius curve. Draw your straight track leading into the curve at 23 inches. Connect and you’re done.
Hard to describe, but you’ll see it right away if you draw it.
That Easement needs to be about 18-24 inches in length. Start it about a foot or more from the curve and end it about the same distance inside the curve.
