Designing a Track Plan for an O Gauge Model Railroad Layout

Page 4: Designing Trackwork for our Spare Bedroom O Gauge Model Railroad Layout

How much model railroad track can we fit on our layout?

Setting priorities for operating capabilities

free model railroad plans, design, layout, trackwork, O Gauge
Figure 15: Basic tools are all that are needed to design trackwork for a model railroad layout.

On the first page of our O Gauge Layout Project we worked through the pros and cons of several locations for our railroad empire, and on page two we decided how much space we could allocate to the pike in our spare bedroom. On page three we built the benchwork (the tables the to which the track will be affixed) for the space we had picked. Each of these steps required a number of decisions and compromises with our plans for a dream layout.

Free model railroad plans, layout, design, tools, CTT, Track, Template
Figure 16: CTT Track Template for O Gauge.

Constraints on space, as well as budget cause any number of compromises in model railroad layout design, but just because you can’t build one of those massive around-the-walls point-to-point pikes featured in the hobby magazines doesn’t mean you shouldn’t build what you can. And, the experience you gain in building a small model railroad layout will help you when you decide to tackle a larger pike.

With all that said, now comes some serious compromising. Remember on page one we created a list of what operating features we wanted on our O Gauge Layout Project:

  • offers continuous running of at least for two trains;
  • Has sidings to drop off and pick up freight cars;
  • I’d also like a railroad yard, but will probably have to settle for a passing track with a spur;
  • Reversing loops would be nice so I can turn my model train locomotives with out relying on the “hand of God” to pick them up and flip them.
  • An up-and-over figure 8, as well as other changes in track and terrain height.
  • Minimum mainline curves no less than 42”;
  • Last, but not least, I would like one of the continuous loops to have 72” curves, to run my scale 80-foot passenger cars. They will run on 42” curves, but they overhang a lot, and look pretty silly.

That’s a lot to ask for a model railroad layout that must fit in a spare bedroom. In fact, that’s far more than we can ever fit in our space in O Gauge. Probably too much even for HO Scale. To get all of these features in this space, We’d probably have to go down to a N Scale model railroad layout. But, I just don’t enjoy working at such a small scale. So, It’s time to prioritize.

I would have to prioritize my 72” curves on the outer loop as number 1. On pages two and three, we made concessions on shoulder room at my drawing table to achieve those 72” curves, and built the benchwork specifically to include them, so they have to stay. This baseline also allows 54” and 42” curves inside the outer loop, so our minimum 42” curve requirement can also be met.

While I could meet the “two trains continuously running” wish, the amount of real estate it would take might be difficult to achieve this and any of our other considerations, so I will settle for one train running continuously, and another working off the mainline that will require nearly continuous operator interaction. I also really would like an over/under figure 8, and it would work well for the Southwest U.S. mountain terrain I want to model.

A railroad yard is out of the question, but I think we can work in a siding or two. Sidings will all have to be inside the 72” loop, since that runs at the outside edge of the benchwork. We may be able to combine the sidings into the inner loop in the way a meandering small town siding works, where cars are dropped off at various points of the same track rather than building expensive switches to create stub sidings.

And finally, the entire inside loop can be designed to create a reverse loop to return trains to the outer 72”mainline loop, however, it may not be possible to turn the trains that have returned to the outer loop back onto the inner loop. But, since it’s a loop, the locomotive could be decoupled from the train and run around to couple onto the other end of the string of cars. There are some prototypical examples of this maneuver, but it would work best with a double-ended diesel locomotive.

So, now that we have our operational priorities, it’s time to get down to designing our trackwork. There are many ways to design your model railroad layout trackwork. If you have a big pile of sectional track laying around, you can just start putting it together to see how it fits. I had quite a bit of O-27 sectional track, but would have to buy more, so I wanted to develop a plan to decide what track pieces I still needed to purchase.

There are a number of computer programs that can design a model railroad, but since the theme for this project is to do what we can inexpensively, I opted to go “Old School.” You can design a model railroad with nothing more than the tools shown in Figure 15: a compass set, a protractor, a ruler, some graph paper, and a pencil. I like to use colored pencils as well to give some visual separation when there’s a lot of lines on the page.

Free model railroad plans, design, trackwork, layout, benchwork
Figure 17: A kidney-shaped loop of O Gauge track with 72″ diameter curves.

Another handy and inexpensive tool for designing a layout that will use O Gauge tubular track is the CTT Track Template shown in Figure 16. This is a good way to go if you don’t already own a compass set, as a good-quality compass can cost more than the CTT Track Template, and a poor-quality compass is worse than useless, as it won’t hold its size when you draw a circle, so nothing will line up. Although they used to be a common accessory stocked by hobby shops, with so many computer model railroad design programs available out there, you may have to do some searching to find a CTT Track Template. If you can’t find one in a local hobby shop, search online, as they are easy to find there.

To start, I redrew the model railroad layout benchwork to the same scale as the CTT Track Template, where one inch on the template equals one foot of actual space on your model railroad layout. Expressed as a ratio, it is 1:12 scale, that is, one inch on paper equals 12 inches on the real layout. I drew this on the four-to-an-inch side of the graph paper for purposes of easy division. One square would then equal three inches. This size created a drawing larger than one 8 1/2” x 11” graph paper, so I had to tape two sheets together.

Using the CTT Track Template, I drew several layout ideas on thin cardstock and cut them out to see how they would fit on the graph paper layout. My final design for the outer loop is shown in Figure 17. I threw an S-curve into the simple 72” loop to take full advantage of the space on the short leg. When designing an S-curve, be sure to put a straight track in the middle before reversing the direction of the curve, or you will have a potential derailment point as train cars make the drastic change from turning left to turning right. I only had one complete circle of 72” track, which, to my knowledge was only manufactured by the now defunct K-Line company that was absorbed by Lionel, which no longer offers it. So, the S-curve at the bottom right of the outer loop meant I didn’t have enough track for the curve at the top right. Since this area will be hidden later, I substituted 54” track for the curve here. My long cars will run fine on 54” curves, they just look better on the 72” curves.

free model railroad plans, trackwork, design, figure 8, 54"
Figure 18: Adding an over/under figure 8 loop with 54″ diameter curves

In Figure 18, I replaced the first straight section coming out of the bottom of the 72” curve on the left side of the drawing with a left-hand 42”switch to lead into the inner loop. This again required an S-curve fit a 54” curve inside the 72” curve on the right side of the drawing, even with a couple straight tracks added. Even then, according to the template shapes, it will overlap the outer loop. This shouldn’t be a problem, as the inner track will be going up in elevation (or “upgrade”), and should be high enough to pass over the outside loop. More on railroad grades and elevating track here.

So, to include my over/under figure 8, the 54” curve continues around until it is heading “down” in the drawing. The track will reach its maximum elevation about the middle of the layout, as noted in Figure 18. From here the track begins to descend, and turns left on the drawing to another 54” curve back down to table level. Where this 54” curve ends at top left, we’ve added another 42” switch, this one right-hand, to allow us to create our reverse loop of 42” diameter curves to start the train on its return journey over the figure 8 to the 72” mainline loop. By breaking the electrical connections of the track into “blocks” that can be independently powered by different transformers, one train can operate on the outer loop continuously while another operates on the figure 8. The train operating on the figure 8 cannot operate continuously in one direction, however, without ending up back on the 72” mainline, so it will have to be tasked with simply moving cars (switching) to various industrial locations located along this secondary train line.

So, at this point, we have met the following points in our operational “wishlist”:

  • One continuous loop with 72” curves to run my scale 80-foot passenger cars;
  • An up-and-over figure 8 that changes track and terrain height;
  • Minimum mainline curves no less than 42”;
  • Reversing loops to turn my model train locomotives (well, in one direction, anyway);
  • Sidings to drop off and pick up freight cars (the entire inner loop is sort of a siding).
free model railroad plans, trackwork, spur, sidings, stub, layout, design
Figure 19: Adding spur sidings to the inner figure 8 loop of our model railroad layout.

However, we may be able to do a bit more to satisfy that last item with he addition of two more 42” switches on the inner loop, as shown in Figure 19. A right-hand switch in the center of the 42” diameter reversing loop on the right side of the drawing creates a siding that will cross the diagonal straight of the return loop at a 45-degree angle, which creates an interesting bit of trackwork. A left-hand 42” switch at the end of the diagonal straight of the reversing loop creates another spur siding at the top left of the inside loop. These two spurs could be joined with another 42” diameter curve, portions of which could be hidden with buildings or other scenery to keep the impression of spur sidings while giving one more reverse loop for our switch engine to run around the cars it’s spotting along the right-of-way. But that decision will be left for a later time, when I see how much real estate is left for industrial structures in that area.

free model railroad plans, trackwork, design, test, fit, O Gauge
Figure 20: Test-fitting track on an O Gauge model railroad layout

The CTT Track Template is not an exacting tool, so I did do some test-fitting of track as shown in Figure 20. This test-fitting indicates I may be able to squeeze the inner 54” loop enough that it will fit inside the 72” loop without having to cross above it. This will help keep our elevating grade for the over/under figure 8 from being too steep for the trains to climb. Be sure to read our Railroad Grades Tips and Tricks page on how to calculate gradient percentages when elevating model railroad track from one level to another.

Go to:

Page 1: Deciding on a Location for your Model Railroad Layout
Page 2: Deciding How Much Space to Give Your Model Railroad Layout
Page 3: Building Benchwork for Your Model Railroad Layout
Page 5: Building Roadbed for your Model Railroad Layout

Please Support is entirely user supported. If you find something of value here, please “pay it forward” and help us keep the site operating by a secure donation through PayPal (PayPal account is not required), or by shopping with our advertisers.

Thank you for your support!

How Valuable to You is

8 thoughts on “Designing a Track Plan for an O Gauge Model Railroad Layout”

  1. Could you please let me know where I can purchase a magazine showing me various track plans and showing the amounts of different tracks per. plan. ie. straight,curved. Note: I am also a big fan of rail yards for lots of switching!! Thanks very much!!! Mr. Hughes

Leave a Reply

Your email address will not be published. Required fields are marked *