I’ve been reading through John Armstrongs “Track Planning for Realistic Operations”, and I’ve enjoyed the book thoroughly, but there is one area that has me a bit twixed, and I can’t grasp it. I thought I’d throw this in here in hopes that someone can explain it a little more in detail and easier to understand.
Armstrong wrote about the “squares”, and using that to plan a layout? I can’t quite grasp what is being explained. How do you come up with a size for your square? OR are all squares the same size and you use that as a template?
In Figure 6-1 John defines the size of a square as the minimum Mainline track radius pluss 2 times the trach center spacing.
S=r+2c
If for instance: In HO scale you chose 24" as your mimimum main line radius and 2-1/2 inches as the track center spacing the a suuare would be 24+2x2.5 = 29"
The square can then be used to help determine what will fit in your model railroad space.
In the book Armstrong shows what will fit into the squares. Thus you know that in an area 2 squares wide you can fit a half circle with passing track. Similarly there are diagrams showing how many squares a yard latter will take and so forth.
The idea is that when idly doodling trackplans, you have an idea what will fit in your space by dividing it into squares. Without having to accurately draw everything, you know that half circles fit in 2 squares wide, yard ladders are so many squares long, etc. So you draw a rough diagram of your space in squares and play around with different track ideas.
It depends on the edition of the book what the figure number is. It’s 6-1 ni the second edition and 7-1 in the third.
The key is that you first decide what you minimum mainline radius is going to be, and that leads directly to the square size. Basically the size of the square is set to allow a double mainline, or a main and a passing track to get turned around in a two sqare space. See Figure 6-1 (or 7-1 depending on the edition) for examples. Squares let you do quick ‘back of the envelope’ type figuring so you don’t go too far down impossible paths. It’s tempting to figure you can make sthings fit, but if the squares say it won’t fit, don’t try it. On the other hand, if the squares are happy, you’ll make it.
Ok, thanks for those responses…I think I get it now, but another question comes to mind.
You said that the squares show minimum radius + 2xtrack centerline spacing. So lets say for argument sake that I have an N scale idea, with 11" minimum radius for the curves, which if I’m adding right will come out to 14" squares. 14S=11r+1.5x2c
If I want 18" radius curves as well, do I change the size of the square? That would make a square 21" which is a little larger than the 14" square?
The minimum radius that you choose to define the size of the square defines what will fit in your space. There’s nothing to prevent you from using larger radius curves on the layout. If you don’t change the square size, you’ll need to use the smaller radius in allthe places that define the size of things. If you want to use a larger minimum radius, then you use a larger square size. There’s no free lunch, as they say!
If you change the radius, the square size must also change. They key to the squares method is that it is NOT a precise drawing tool - it is more an aid to the earlier informal sketchign you might do. By the definition of the square, you know a 180 degree turnback will fit in 2 squares. A complete circle takes 2x2 squares, 4 total. By looking at the definitions in the book you can see how many turnouts will fit in a square. Thus when you are making random doodles or have an idea away from the computer (if you are using CAD), you can quickly sketch it in place and know what you are trying will fit. Freehand sketching often results in some unintentional compression where you squeeze track in that won’t fit if actually built. The squares method prevents this. Like if that extra space you find at the edge of the room is only 1.5 x 2 squares, you can’t POSSIBLY fit a turnback curve at your minimum radius.
The idea is to get the basic shape of the track plan to fit the space using the squares, then make a ‘final’ plan plan drawn to detail. One thing I didn’t like about the latest edition of TPfRO is that whole section on the evolution of a track plan is reduced to only a couple of pictures - in older editions it is more pages and pictures. IMO this is a critical part of track planning and probably shouldn’t have been cut down - mainly to make room for the extra chapter on ‘modern’ railroading.
I’m gonna use an analagy to see if I grasp that concept-
If I were to design the furniture layout in a house I would draw a scale dwg of where the walls, windows and doors were (same as max. layout size) and also determine the size of each peice of furniture to go in it (perhaps with cutout templates showing a sofa being twice the footprint of a recliner and etc?)? At this point I would position the templates until I was satified with the result.
Thank you tremendously! I have had the SAME exact problem as this fellow with Armstrong Squares for quite some time now.(And, from the same book!) And you have just shot that problem out of the air! [:D]
That’s pretty close, though in a way it is a step short of templates. It’s more like you say I want a ‘large’ house, that leads to the standard unit of size (the square) being a certain size. You know how many squares you have, based on the size of the squares and the size of the space. Then you know that a kitchen takes some number, a master bedroom some number, etc. In a smaller house, each room takes the same number of squares, but the squares are smaller. There are flaws in the analogy, but that’s a shot at it.
The main thing to keep in mind is that the Armstrong Square is a tool used when track planning is in the ‘sketch on the back of an envelope’ phase, not for final pre-construction design.
The squares are a tool, not a straitjacket, and there’s no rule that says you can’t superimpose squares of two different sizes on the same space. The larger squares will allow you to work up your mainline, stamping ground of 4-8-4s, E-units and full-length pullmans (or 89 foot humonguboxes.) The smaller squares can be used to rough in the tight-radius branch where consolidations or GPs run ore cars to and from the mine.
Squares serve one very basic purpose. Using them, you are not too likely to design something that’s impossible to build.
Thank you all for your thoughts and answers on this; I think I have a better working concept of the squares now!!
I already have an Nscale layout in the works, but this will help with any additions that come up for consideration, or a possible HO layout on a deck above the N scale layout! Thanks again for your replies!
Remember too that when the tracks curve - say at the corners of an around the room or an around the basement walls layout - if you have a double track mainline, the inside track has to be your minimum radius, so the outside radius has to be a couple of inches larger. So in HO if you want a 30" minimum radius and are running a double track mainline, the inside curve will be 30" and the outside 32". If the outside was 30" then the inside would have to be 28" - and your minimum radius would be 28", not 30".
Keep in mind too that the spacing between the two tracks is different in different scales, I think the 2" approximation is for HO scale, it would be less in N.
To be rediculous and exagerate on purpose to explain why you use squares. Suppose you had a 6’ wide and 10’ long area and decided to fill it with a railroad. mentally you said, “Ok I am going to start in one corner and go around the wall, make a 180 degree bend and come back down the center of the room to where I started and make another 180 degree bend to go back the other side of the island and make a 180 degree bend to come down the other wall and then connect the end to where I started to make a loop. Not a bad plan and done all the time. The question to be answered however is can I really do that. Since my space is 6’ wide a real quick and ditrty calculation would say each time I make that 180 degree bend I need at least twice the radius of track I want to use (or the diameter of a circle). So 24” radius x2 = 48". add 2.5" for track center and each 180 degree bend requires 50.5". Since Ihave two 180 degree bends at one end of the room I need twice that amount or 101" in width or two squares. I can’t do that since my room is 6’ wide or 72". nic mental plane but a quick and dirty check say’s I need another plan. Now if you have a bigger area you can figure the squares and then draw them in the room on a sheet of paper. Now you can draw tracks into the squares to see what you can do in the way of a track plan.