When I decided to continue model railroading again, I wanted more than just an occasional small layout that lived on the carpet or dining room table. The problem with small oval tracks (or even slightly more complicated ones with a viaduct crossover) is that they’re just not very interesting. For one, there’s really only enough room to run a single train at a time, and it doesn’t take very long to cover the entire loop.
My intention with this new layout would be that it was constructed in Kato Unitrack (which I discussed in a previous article), and run at least two trains at once. I wanted to use Unitrack because 1) I really like its quality and versatility and 2) I already had a bunch. Another necessity was to have sidings large enough that I could have other trains railed up and ready to go. I figured the best way to start was to try to find something preexisting on the internet. What I came across was this site, which had several potential layouts that had already been plotted.
I ended up settling on layout 612 as it had two main lines and options for several sidings. I personally like very busy layouts. There’s really not enough room in any house to sparsely populate a model railroad without drawing too much attention to the fact that you have a train on a small loop running in circles. On the other hand, this one was complicated enough to where I actually had to trace out the mainlines to see how a train would work itself around the track.
There were a few inherent problems with this layout. First, even as a complex as it was, where the mainlines looped back on themselves, all the tracks were too close together. I do like lots of parallel lines, but spreading them out a bit in key areas could give the layout some additional visual depth it did not otherwise have. Given that the original is just under 3ftx10ft, I felt that since it was going to be large anyway, I might as well make it a little wider. The biggest issue to deal with was the 282mm (11in) radius inside curves on the viaducts. I knew from prior experience that my 85′ Pullman cars nearly touched the viaduct walls on a 315mm (12 3/8in) radius curve, so they would likely be rubbing them on the 282mm curves (they do). Needless to say, I needed to dimension more relaxed curves for my home layout. Unfortunately, this required almost a complete redesign.
One failing of sectional track like Unitrack is that the geometry can get extremely complex when you try to run parallel lines or use curved track of more than one radius. It’s very easy to have your tracks not meet when you try to do the final joining. Sometimes they’re slightly too long, or too short. Maybe they end up being offset from each other by an inch. Regardless, unless you want unnatural flexing or bowing in your layout, you have to be creative in your planning. Fortunately, Kato makes a variety of straight and curved track to help ease the task.
My solution with a layout as complex as mine was to design it on the computer. There are several companies that make track planning software that have Kato Unitrack in their libraries. I demoed a few of them, but ended up going with AnyRail. There was a learning curve involved, but it still took longer than I thought it would in order to dimension out a revised track plan. First of all, even when recreating the original layout 612, I learned I needed to relax some of the flex tolerances to make everything fit together correctly. Then, I broke apart 612 into specific sections and started upgrading curves.
It ended up during the planning stage that I figured if I am making two mainlines and some really long sidings, I can just create a simple third mainline on the outside. So, that’s what I did. I’ve also mentioned previously that I have HO scale trains. Now, I do have Atlas sectional track (using copper rail joiners, but it’s not snap track) that I used to setup on carpet as a kid. I tried this in my house and didn’t like the result, so I went looking for an alternative. To my surprise, HO scale Unitrack really isn’t that expensive. I ended up designing an additional simple oval with a single siding that would surround my N scale layout.
What I ended up coming up with was this:
Each of the squares equal two feet. The above fits in a 5 foot by 11 foot area with no room leftover. Without the HO scale loop, the N scale layout is exactly 4 x 10 feet.
Continued with pictures here: https://geekhobbyist.wordpress.com/2010/04/21/n-scale-unitrack-layout-part-2/