In some difficult-to-reach places I have installed Tortoises onto a 1/4" piece of plywood and then attached the plywood to the sub-roadbed. In other places I installed the Tortoises directly to the sub-roadbed. This photo shows the Tortoise, the plywood piece, and the drill template that comes with the unit.
Here is the assembled collection of parts. The arm in the Tortoise moves left and right, which causes the linkage rod to move right and left, respectively, above the layout surface. You may notice that I use a thicker linkage rod than that which comes with the Tortoise. The friction at the points is sometimes too high to overcome with the included linkage rod. If you use a pre-manufactured turnout, you may need to grind down the end of the linkage rod to fit into the throwbar hole of the turnout (or drill out the hole in the throwbar, if you dare). If you scratchbuild your turnouts, you can, of course, make the throwbar hole fit the dimension of the linkage rod. I usually make it a bit larger so that the rod is free to move in the throwbar hole. I have also generally found the linkage rod supplied with the Tortoise to be too short for most roadbed solutions I have employed over the years.
As you can see from the photo above, the screws I used stick out of the plywood, so I cut those off before I installed the Tortoise. After attaching the Tortoise to the sub-roadbed using clamps I was able to fine-tune the location of the Tortoise relative to the turnout.
I also had to bend the linkage rod on this one to get it to throw the points in both directions. It is operating perfectly now. For this layout I also switched from powering the Tortoises with a 9V power supply to a 3V power supply. The turnout now moves just about as slow as you can get, and they make almost no sound to boot (this was before I started using Digitrax stationary decoders). The Tortoise with plywood piece was installed under the sub-roadbed with some drywall screws driven in from above (which makes it easy to install and easy to remove in the future).
This diagram shows my typical installation. The Tortoise is controlled by a Digitrax DS44 stationary decoder. The Tortoise has an internal switch that routes either the DCC bus wire "A" or "B" to the frog of the turnout. I prefer to insert a 1,680ohm resistor (use a 1K ohm and a 680 ohm in series) to slow the Tortoise down a bit. It makes it much more quiet. If you prefer to manually flip a switch (e.g. in a control panel) the DS44 can be substituted with a DPDT toggle switch. That switch can then be fed by a 3 to 9 volt power supply. The other contacts available on the Tortoise can be used to drive a turnout-position indicator LED.
Sometimes it is hard to install a Tortoise under a turnout. Either the benchwork under the track interferes with the Tortoise placement, or it is too close to the edge. Circuitron makes a "remote mounting" kit, but that adds at least another $10 to the cost. Before trying that solution, I always check to see if mounting the Tortoise above the layout's surface is an option. On the P & C Railroad Version 2 I had two such situations. The two turnouts were very close to the back edge of the layout, so the Tortoises just couldn't fit.Sometimes it is hard to install a Tortoise under a turnout. Either the benchwork under the track interferes with the Tortoise placement, or it is too close to the edge. Circuitron makes a "remote mounting" kit, but that adds at least another $10 to the cost. Before trying that solution, I always check to see if mounting the Tortoise above the layout's surface is an option. On the P & C Railroad Version 2 I had two such situations. The two turnouts were very close to the back edge of the layout, so the Tortoises just couldn't fit. The area near the back edge of the layout will be receiving a turnout. I had straight track there, but wanted to add a spur. After pulling up the track, I used a foam cutter to hollow out a groove in the surface of the layout (which was made out of layers of insulation foam). I didn't want to pull up the other two tracks, so the tool worked great for hollowing out under that track. Several passes were required to build the groove.
In this photo you can see two plastic tubes. I believe I bought those at a crafts store, such as Hobby Lobby. The idea is to have a rod/metal wire move back and forth inside the hollow tube. The tube guides the rod. The rod will be connected to the Tortoise on one end and the turnout on the other. The green tube is for one turnout location, and the red one is for a second such installation.
After installing the Tortoise in the desired location, the hardest part is determining the correct length of the rod that connects the Tortoise to the turnout. Some measuring and a bit of trial-and-error is required. The photo shows the rod installed (in the second location, which is why the tube is red instead of green in the photos above).
Here you might be able to make out the zig-zag bend in the wire that (orange-coated) metal wire that runs through the red outer tube to the turnout's throwbar.
Once installed and tweaked, the Tortoises worked great. Obviously, the key to making this whole thing realistic is some way of hiding the Tortoise. The larger the scale you model, the easier it is to hide the unit.
I had several multi-story N-scale apartment buildings that were going to be a part of a town that I was modeling in that layout. The buildings were a perfect fit for the Tortoises. They slipped over them without modification. Because the rod slides back and forth inside the tube, it is perfectly fine to cover the tube with plaster, Sculptamold, or other scenery to hide it. When the whole thing was done, a visitor couldn't tell that the turnout was being thrown from within the apartment building!
For this particular installation, I wanted to mount the Tortoise sideways, because it might be under a building or scenery (don't yet know which one, hence the decision). I measured and decided a 2 x 2.5 inch block of 3/4" plywood would be a good mounting board for the Tortoise. I marked the placement of the screws with a pencil.
Next, I drilled the holes with a drill bit that is about the same size as the shank for the screws. The screws' thread needs to dig into the wood for extra strength.
I have found that the easiest way to install the Tortoise is to first partially install two of screws, and then slide the Tortoise on to them.
I then install the other two screws. Before tightening all four of the screws, I make sure the Tortoise is in the desired position.
This photo shows where on the layout this Tortoise will be placed.
The picture is horribly over-exposed, but it shows the assembly being glued to the layout base. Since this is in an awkward position, I used three metal weights to hold the block of wood down while the glue dried.
The next step was to solder all the wires to the Tortoise. By doing that I could test the turnout, the wiring, and use the active Tortoise to test and debug the throwbar connection later on. The outside wires (red and black) are connected to the Digitrax DS44. The green wire near the center (it actually has a black stripe to differentiate it from the other green wire) feeds the frog rails. Those are adjusted to the right polarity based on the gray and other green wires.
Here are the parts needed to install the linkage rod. The rod is not the one that comes with the Tortoise but a piece of music wire I bought at a local store. My experience has shown that the stock linkage rod is just too flexible to be effective. The one I prefer is 0.040" thick. It has just the right stiffness, yet allows some bending.
To connect the linkage rod to the throwbar, I constructed this connection rod. It is a piece of wood custom fitted for the location. I drilled a hole and glued a piece of music wire in the hole using 5-minute epoxy.
The next photo shows the basic idea. The wooden block rests on the fulcrum guides of the Tortoise. The piece of music wire glued into the wooden block needs to be trimmed to the correct height.
This photo shows the final installation. I drilled a hole slightly wider than the linkage rod attached to the Tortoise. This gives it the freedom to move around while still dragging the wooden block with it. The setup worked right away. The Tortoise is flexible enough to move the points only as much as is needed.
Similar to the sideways installation above, this installation required the Tortoise to be placed on its back. The added wrinkle in this installation was the fact that the long end of the throwbar needed to be away from where the Tortoise was installed, because above the Tortoise there is going to be a station, which is right up against the track. Using some trial and error (using too thin of an actuator rod for starters), and lots of measuring, I came up with an actuator rod shown in the photo. I thought I needed a small piece of thin pipe to hold the actuator rod in place, which is why it is on there. It turns out that I didn't need it at all, but once I made the bends, I couldn't remove it.
After the actuator rod was formed, I installed it on the Tortoise. This then gave me an idea of where the Tortoise needed to be mounted for the rod to properly connect up to the hole in the throwbar. I made a mark on the benchwork, and found a piece of wood to which I could attach the Tortoise.
Because of the thickness of the actuator rod, there is actually quite some pressure on the rod and Tortoise connection. At first I was worried about how to glue this whole assembly to the benchwork while also being connected to the throwbar. I found out the hard way that the actuator rod can be completely removed from the Tortoise after the Tortoise was installed. So, in this next photo you see the setup I used to hold the piece of wood to which the Tortoise was connected down with a lot of weights while the glue dried. The actuator rod has been loosened from the Tortoise to avoid the afore-mentioned pressure.
And here is the final setup with all the wires connected to the Digitrax DS44 stationary decoder seen in the background. Once the structure is in place, this installation will be completely hidden.
I wanted to cut off the actuator rod sticking out above the throwbar, because it is unsightly. However, the distance it sticks out is necessary. After looking at it more carefully, I discovered that the rod actually falls down a bit when it gets in one position. So, a thought occurred to me to just make a small upside-down table that prevents the rod from falling down. You can see the "table", made of some scrap wood in the photo. It is shown in the approximate position it will be installed under the sub-roadbed. At first I clamped it in place to see if it would work, and it did. I then used carpenter's glue and permanently installed it. Now I can trim the actuator rod to just above the throwbar.
Here is an overall view of the installation of the two Tortoises described above.
When the Tortoise needs to be mounted quite some distance from the turnout, I use a ruler to make sure that it lines up with the angle of the turnout, as shown in this next photo, which is in another location from the ones shown above. The weight on the Tortoise-mounted block of wood is to hold it down while its glue is drying.