Saturday, December 19, 2009

Designing my train layout - 5 - double track

While leafing through the Armstrong track planning book, I came across this diagram that changed my thinking drastically. The thing that caught my eye was this text from one of the captions: "In model practice, where mainline length is severely limited, two and three track railroading may actually surpass single-track operation in variety"."

Most of the trunk lines in India are double track (with the Chennai-Mumbai section being the only important route with a lot of single track). Upon reflection, I realized that what I wanted was a lot of parallel action. Furthermore, the station configurations could be made more realistic. I then decided to give double track a try. I started by taking a fresh look at the "water wings" configuration from a double track perspective:

The results were surprisingly good. I was able to fit two stations that each had a single passing loop shared between the two tracks. I have, in fact, seen this layout in some small stations on double line sections in India:

Although promising, there were two issues:

  • Lack of visual separation between the stations. The two stations are physically close together even though there is a nice long run between them. The only obvious solution was an oval. Now, I had initially rejected ovals because I though they looked boring. However, it was clear that a good old oval is what would work best for me.

  • I came to the conclusion that I wanted the stations to have different configurations. Specifically, I wanted a conventional double station as shown in the next diagram. Although configuration B would be more prototypical and offer greater operational flexibility, I was willing to settle for configuration A. The point is - it looks like a regular double track station.

At this point, I showed the last design to my friend Dale Schultz who has built a large Marklin layout. Like myself, Dale is interested in using computers to automate train operations. He is a very sharp thinker whose judgement I greatly respect. He told me I was on the right track but suggested that I reduce the number of sharp curves. The next design I came up with was this:

This was now getting interesting. Notice that the lower station remains curved. This was intentional - I had come to feel that at least one of the stations ought to be curved for aesthetic reasons. The two problems were that the passing sidings in the upper station were too short and there was only one cross over and it was too far removed from the nearest station. The next step was to integrate the crossover with the upper station, thus:

This was definitely an improvement. There was a pleasing curve to the upper station and both stations had passing sidings of acceptable length. Dale suggested investigating curved turnouts. I looked through the Walthers catalog and found that the Shinohara #7 curved turnout would be perfect for my needs. This turnout has radii of 24 and 2.8.5 for the diverging and normal routes. This is the next design I did incorporating curved turnouts for the crossovers.

I felt that I was closing on the final design. The last tweak to the design was to confine all the curved turnouts to one side of the layout - mainly for aesthetic reasons.

And that did the trick. I was now fully satisfied with this design - The full process had taken about seven weeks but it was time well spent. A 3D view is shown below that includes the benchwork. I am deliberately not using the space in the center of the layout for the time being. I may eventually come up with some use for the space but it will be left vacant for the time being.

In my next posting, I will explain the operational possibilities of this layout.

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