Innovations

Laying out the viaduct it became obvious that the branch right of way needed realignment. While this could have been avoided with "proper planning" I don't work that way. Despite all the fuss about it from some modelers I don't mind doing it twice (or more). If the end result is what I can live with it was worth the extra effort.

Fortunately, the styrofoam spline I use for road bed is very forgiving. You can realign it very easily. It gives to a certain extent. A curve can be formed to a tighter or wider radius just by screwing the spline in the desired position. I chose not to do that, however, and created a new section of spline instead. I added a few "innovations" to the new construction.

The roadbed can be cut with a razor, exacto knife etc, but I chose a Zona saw, what I call the "short sword". It's a keyhole saw of sorts, with a very pointy end that's great for pushing through the foam when need be.

First I cut out the section I didn't want anymore. I lifted the whole thing off the layout and set it aside...

Removed Spline

You can see that, once the glue dries, it's easy to remove large sections. The spline also maintains its shape, very convenient in case you want to use it somewhere else. I'm not reusing this piece. Instead I'm laying new spline.

The first step is to cut more spline strips. I use my trusty straight-edge, originally meant to cut drywall. It came in two four foot sections. I modified mine so it is permenently eight feet log. It has a stop along its length made of channel set to cut 2" strips. The cutting side is square to the foam...

Straight-edge

I simply lay it over the 4' x 8' by 1/2" foam and run a razor blade along it. In the past this has worked, but the cut was not always square, so the spline top wasn't level width wise. Most of the issue was caused by me, cutting too fast to be accurate. This time around I went slower, cutting in several passes and pressing the utility blade hard against the straight-edge to ensure the cut is square...

Slow Versus Fast Cut

Once the strips are cut I start building the spline itself. First I notch the existing spline so it overlaps the center strip...

Notched Spline

The notch creates a stronger joint and centers the new section. I coat the joint with glue and drive in some drywall screws to act as clamps. Most of the time these screws are left in place to help hold the spline together...

Splicing Splines

In the past I've created the entire spline at benchwork level and then elevated it. This works well, but this go around I decided that all I really need to construct is the center strip. I elevated the strip starting at the known height of the viaduct at Quotidian. I used other existing supports as height guides. Rather than using stacks of leftover foam I created notched pylons. The pylons support the strip, the notches keep it centered....

Old Supports, New Pylons

I made the pylons all the same size, necessitating a second piece to raise the spline to the proper height. All the new supports are two piece, rather the hodge-podge stacks of various thickness foam. Thinking back on it the pylons should be fashioned from one piece of foam cut to the correct height.

Once the center strip and pylons were located and glued in place I started on the outer strips. With all the earlier splines all the strips were continuous. In this new construction the outer strips only run between pylons. Once again I use a combination of glue and screw to hold the strips in place...

New Spline

In areas where I thought I might need to change the curve radius I also installed "outriggers". This is just another spline strip running on either side of the supports.

There are several places on the branch that required special handling. The first is where the branch crosses over the mainline inside the mountain. There is not enough room to fit a standard pylon. I had to create a "bridge" to support the roadbed. I used a section of plywood mounted to the lower supports...

Roadbed "Bridge"

The other location is where the branch and the mainline pass under the mine. This is another mountain with tunnels for the mainline and the branch. I placed my NMRA clearance guage to see what needed to be removed....

Clearance In Mine Area

Rather than mess about with modifying the existing roadbed I simply removed and replaced it with a large section of plywood supported on substantial foam blocks...

Plywood Mine Support

The one place I found the most troublesome was the corner at the far end of the viaduct. The track gets VERY close to the layout edge. I filled in the entire corner so I could create a tight curve with a nice transition...

Filled Corner

With the spline complete I have to make places to add all the bridges I'm building. This will require some more cutting and trimming.

Regards

Frank Musick