What's New & How To
Our ever-changing "What's New & How To" feature will highlight everything you want to know about MRC products and your hobby and market trends. There'll be how-to articles and new product announcements. You'll find FAQs on our products, new videos and fresh modeling concepts. Start exploring and come back often to check out the constantly updated information and current hobby ideas.

Friday, September 23, 2016

Model Railroading: A Multi-Dimensional Hobby - Part 3

Model Railroading: A Multi-Dimensional Hobby - Part 3 - Track Planning

This is the part 3 of a series of articles exploring the changing face of model railroading and how it continues to evolve into a contemporary, varied, fulfilling and exhilarating hobby.

The last article discussed the development of the benchwork for the layout. The main job of the benchwork is, of course, to hold up the track. So it begs the question of what to consider when developing a track plan. This article will take a high level look into the various considerations of track planning. Note that this is only a high level look. Dozens of books have been written discussing model railroad track planning ideas. Additionally, hundreds if not thousands of track plans have been presented in various magazine and on-line articles. Furthermore, there are on-line groups that have members who constantly discuss the various nuances of different track plans. This article is a very brief introduction, I encourage you to do additional research as your track plan is developed. A lot of time goes into a layout, so it’s best to invest some time up front to be sure you end up with something you like.

Yards are busy places where the railroad breaks up and makes up trains.

Track Planning Basics
Before pulling out a pencil and pad, or even your favorite software, take some time to consider what the purpose of your layout actually is. If it is your first layout, it’s probably best to keep the track plan simple; perhaps a loop with a siding or two. This is also ideal to get some techniques and skills developed before embarking on a larger project. On the other end of the spectrum is to model a specific prototype or a large operating model railroad. Some folks want to model a particular scene or region or develop a specific operating scheme. This can be a lot of fun, bringing together hobby interests with researching history. Most people shoot for something in between. 
The next step is to develop a list of “givens and druthers,” a term coined by the late John Armstrong, generally considered to the dean of track planning. Check out his book “Track Planning for Realistic Operation” for an excellent treatise on this topic. On this list “of givens and druthers” identify all the key elements you want included in your plan. Givens are, of course, the elements you really want. Druthers will be elements that you would like, but are negotiable. Also include some design criteria such as:

  • Minimum Radius: what is the ‘sharpest’ turn you would like to see on the layout? This will generally define the type of equipment you can run. The last article included some considerations on track radii, presented again for reference: Model railroad radii are generally categorized into “sharp,” “conventional” and “broad” curves. The following table summarizes these for some of the most popular scales:
Curve Category O-scale HO-scale N-scale
Sharp 36” or less 18” or less 9” or less
Conventional 48 — 60” 24 — 30” 12 — 15”
Broad Greater than 60” Greater than 30” Greater than 15”

  • Maximum Grade if you are using differing elevations. Grade is generally expressed as a percent. One percent grade means it will raise one foot per hundred feet of run; 2% = 2 feet per hundred feet. Of course, feet of rise are pretty extreme on a model railroad, so generally it’s measured as so many fractions of an inch per foot of run. A practical maximum grade on any layout is around 4% with 3% allowing for much more reliable operation. Many owners limit their layout to 2% or less.
  • Clearance between tracks. For trains to cross over each other, there has to be enough space between the tracks. In HO, for example, this is typically considered no less than 3”. Less than that, and it makes supporting the track difficult, or if even less, risk of tall equipment not fitting through the crossing.
  • Height above the floor. Placing a layout close to the floor makes it uncomfortable to operate. However, if small children are going to be using it, keeping it within 2 feet of the floor is probably good. A very comfortable height for building and operating is roughly 3’ above the floor. Moving into the range of 40”- 50” provides a much more realistic perspective when running the trains. Some layouts extend even higher, reaching above head height. These are generally associated with double-deck layouts, allowing much more model railroad to be built within a fixed area.
  • People space. Sounds obvious, but it is so very tempting to fill up a space with a layout only to find there is barely enough room to get in and out of the space, let alone if others are there as well. A good rule of thumb is to provide 3 feet of width along the layout for people access; less for short distances if needed to accommodate some design feature; more if there will be people congregating in a certain area like yards.
  • Reach access. While layouts with large expanses of scenery look great, access will always be required to build the scenery and track, as well as to repair and maintain the layout as required. A good standard is to be able to reach everywhere with no more than 30” from the nearest edge of the layout. This will be reduced if the layout is higher. Some layouts are much narrower, with widths or reach-in depths of 16” or less.

Once a concept and criteria have been developed, the next step is to develop some conceptual sketches. These are not necessarily exact, but close to scale, showing the major pieces of the plan: the space available, the main line, maybe some constraints. So pull out a sketch pad (one with graph paper works very well), a soft pencil and an eraser. Optional is a straight edge and compass or circle template. Box out the space you have available. First step is to lay in the key curves of the mainline. Get a feel of the radius and diameter of the curves as it is laid in the available space. You may be surprised how quickly the space is consumed! Once the turns are defined, connect them with straight segments and look at the overall track plan. Does it make sense? Then move on to adding some locations for cities, signature scenes or other elements. 
As mentioned, a lot of inspiration can come from books, magazines and on-line. Some of these plans may have elements or signature scenes that really appeal to you and you would like incorporated. In those cases, print out the plans and designs of interest to approximately the scale you are sketching in, and cut out the part that appeals to you. Between the paper and pencil, and optionally taping the elements onto the area you would like to see it, the plan can be developed to include your designed segment. Keep in mind plans can be flipped or mirrored to make them work better. Most home PC photo viewers have the option of easily making these edits.

A remote industry along the tracks can make an interest scene and provides enjoyment in switching.

As the plans are developed, some additional considerations should be addressed:

  • Parallel tracks spacing
  • Curved track spacing
  • Avoiding S-curves — trains have a hard time negotiating them. If you have to have S-curves, provide a short straight segment of track between them.
  • Keeping at least 2-3 inches between the edge of the layout and the nearest track.
  • Any kind of reverse loop — a place where the tracks loop back on themselves, will require special handling of the power feed.

Most people find they will develop several dozen sketches as they sort out options and ideas. As mentioned, a lot of good ideas can be found looking through track planning books and articles. The internet also is a great resource for ideas. Sketch, gather more ideas, modify, resketch... repeat. Once you have a plan you like, go through the checklist and criteria again to see if there were any compromises. If you see some, go back to the drawing board. Fudging dimensions in the planning stages guarantees problems later on.

S-curves can be bad if they are short radius and without a straight section of track between the turns. Open up the curves and add a little straight section, and they can become center-pieces of the layout scenery. Sidings are to provide a place where trains can pass.

S-curves can be bad if they are short radius and without a straight section of track between the turns. Open up the curves and add a little straight section, and they can become center-pieces of the layout scenery. Sidings are to provide a place where trains can pass.

A few other points to be considerations as the track plan is developed :

  • Continuous run vs not. A continuous run design allows a train to endlessly circle the layout. It’s a great way to “just run trains” as well as to allow locos to be broken in without a lot of fuss. That said, if you don’t have the room for a complete turnback, a simple “point to point” layout can be fun too. The prototype railroads rarely have turning loops, and most trains are run point to point, where they are broken down at each end of the run.
  • Mainline vs switching areas. Is your interest in running long trains through rambling scenery? Do you like the idea of running a local in and out of industrial spurs to pick up cars? Both can be fun.
  • Staging. Staging is a place for storing trains when not needed. These can be open, resembling a yard, hidden, say behind a partition, located in another room, or above or below the layout itself.
  • Freight yards. A place to break up and make up trains.
  • Passenger Terminals. A place for passenger trains to originate, terminate or pass through.
  • Sidings. Tracks to allow trains to pass each other.

A congested industrial area can keep an operator busy for the better part of an evening!

Detailed Design
Once the rough layout of the conceptual track plan is developed, the work moves into developing a detailed design. Until now, sketches were sufficient, it now becomes important to detail each and every element of track. This can be done either by the old fashioned pencil and paper method or by a CAD program. If going the pencil and paper route, it’s often helpful to purchase a template to make sure switch angles are correct, radii are consistent and so forth. CAD programs range from free downloads to fairly sophisticated packages that include a 3D rendering of the completed layout. Some even let you run virtual trains on the computer, a good way to test run your layout before the first stick of wood is cut!

Keep in mind cross-overs are s-curves. Here we see 85' cars negotiating a #6 crossover. Note the off-set on the car ends. Doable, but not at high speeds. #8 switches would have done much better here. Longer cars look better on larger radius curves.

Once the detailed track plan is completed, it’s a good idea to copy it or print it out, and hang it up someplace and let it gel for a while. You will likely find the plan requires tweaks, adjustments and modest improvements. That’s fine. Mark up the drawing and make the changes. The track plan will never be perfect, but once it reaches a level of comfort, it’s time to start building. Even once building starts, it is likely that you will find some adjustments and changes that are necessary or even just desired. That’s OK.

Make It Happen
As mentioned, this brief article only scratches the surface of track planning. I strongly encourage you to get a few books on the subject. Check out some track plans that appeal to you. If you have the option, visit a few layouts that are similar in size and concept to what you are interested in building. Share your ideas with others and ask for feedback. With a good plan, you will find the layout will come together nicely. Track planning can actually be as much fun as developing the layout itself. It is, after all, a hobby. Enjoy the process!

Author: Detlef Kurpanek

NOTE: Finding the right Track Plan
Probably the best track planning book I have every come across is “Track Planning For Realistic Operation,” by John Armstrong.  There are a lot of other track planning books out there as well. Find one that fits your interests, budget, and available space. Another resource is Model Railroader’s track planning database:  http://mrr.trains.com/how-to/track-plan-database  Any internet search will also yield dozens of plans. Finally, don’t discount considering prototype locations and “selectively compressing” the key features into the layout space you have available.


  1. This was a great series.
    Thanks for sharing it.

  2. This was a great series.
    Thanks for sharing it.