Narrow Gauge Gazette logo Jan/Feb 2021
Volume 46, No. 6

Feature

An Inexpensive Turnout Controller

Throwing Points and Routing Electricity

by Gary Bothe / photos by the author

The On30 switching layout I described in the July/August 2020 Gazette has seven hand-laid turnouts. Another On30 layout I am working on has twenty-three turnouts. To save time, I used Micro-Engineering (ME) flex-track and turnouts in most places on my new layout. After all, given my age, I wanted to live to see that layout in operation. Commercial turnouts cost $20.00 to $25.00 each, but to my dismay, I discovered that commercial turnout controllers are just about as expensive. So in order to save money and challenge my ingenuity, I decided to devise a turnout control system of my own that would be fairly simple, highly reliable, and above all, less costly. What I came up with fits those requirements and allows me to throw points and route electricity for about $8.00 per turnout, linkages included. Both of my layouts use this system and I have found it to be totally reliable over years of operation. If you decide to try my system, I recommend mass producing the units, maybe a dozen at a time. You can work more efficiently this way and later on, as your layout progresses and you install more turnouts, all you need to do is go the shelf, pick up the finished components, and do a 20–30 minute installation.

Turnout Preparation

I have found that ME turnouts can use some preparation on the workbench to improve their function and appearance, and make them easier to install. The turnouts come with a dead frog, which is all right for long-wheelbase locomotives, but if you are running Porters, a gas-mechanical, or some other short-wheelbased “critter,” every bit of rail needs to be available for electrical pickup in order to get reliable operation. ME suggests soldering a frog feeder into the hole in the bottom of the frog, but when I tried to do this, the result was usually a cold solder joint or melted ties, and most often, both. As a result, I devised a procedure that connects a frog lead without soldering to the turnout. Some other simple operations can improve the turnouts as well. Follow Photos 1-4 to see what I did.

Photo 1: Attach a frog feeder by drilling all the way through the hole in the bottom of the frog with a #50 drill. Then tap the hole 2-56 from the bottom up, but stop the tap when its tip reaches rail-top height. This leaves a tapered thread which will bind a screw when the screw tip gets to about the bottom of the flangeway.
Photo 2: The frog feeder is soldered to a brass 2-56 screw at least half an inch long. This will be dipped in anti-oxidizing compound and screwed into the frog when the turnout is ready for final installation.
Photo 3: My ME turnouts did not come with weathered rail, so I sprayed them a rusty brown after masking the area where the points make electrical contact with the stock rails. Buffing paint off the railheads revealed a height discrepancy between rails and frog (circled areas). I ran a flat file across the turnout to eliminate the worst of the problem and then polished the railheads with 1000 grit abrasive paper.
Photo 4: Installing rail joiners on turnouts at the workbench makes it more convenient to connect more track later. Use a small file to taper the base and web of the rail ends to make it easier to get rail joiners on, and remove any paint on rail ends where joints will be soldered. (Taper the ends of all your other track components as well).

Constructing the Point Movers

You will need some one inch wide 1/8-inch-thick aluminum strip, available at your local hardware store in three-foot lengths. One length will make nine of the brackets described here. Also required are DPDT toggle switches, some fender washers (a washer with an outside diameter much larger than its hole), some brass strip, music wire, brass tubing and wood screws. Cut, drill, and bend the aluminum strip to the dimensions shown in Figure 1. I used a small metal-bending brake for the bend, but a sturdy vise and careful use of a hammer will do the job.

Figure 1. Point thrower bracket is made of sturdy one-eighth inch thick aluminum strip one inch wide. It holds the DPDT switch that moves the points and directs the correct electrical polarity to the frog. The small hole on the long leg is the pivot point for adjusting the controller. A wood screw with a fender washer driven through the large hole nearby locks the controller in position when adjustment is finished.

The DPDT switch moves and holds the points. Only one set of contacts is needed to control frog polarity, but the extra set on a DPDT switch may come in handy some day. I like DPDT switches that are screwed together because they can be easily taken apart to slot the toggle handle. This may not be necessary, but I did it to avoid stressing the switch while sawing the slot. If you take it easy, or use a slotting method less aggressive than a hacksaw, you may be able to leave the switch intact. If you do take the switch apart, put it back together again before you glue in the extension strip or you will not be able to get the handle through the hole in the top of the switch.

A one-inch strip of brass a quarter-inch wide and .030-inch thick is used to extend the switch handle for more mechanical movement when throwing the points. See Figure 2 for the dimensions. In my switches, the handle is a form of pot metal and will not take solder, so the extension strip is secured in the slot with ACC. If you make the extension strip fit snugly into the slot to begin with, ACC will produce a totally adequate bond. Test the joint by applying force by hand. (Over many years of use, I have had just one of these joints fail, but it was probably because the slot was wider than it should have been.) With the extension strip installed, attach the switch to the aluminum bracket as shown in the photos and place another drop of ACC between nuts and bracket to make sure things don’t work loose. Photo 5 shows the assembled components.

Figure 2. A brass extension fits into a hacksawed-slot in the switch handle. The center hole accepts a clevis on the end of a model airplane push-pull tubing and the end hole receives the turnout throw wire.
Photo 5: An aluminum angle (Figure 1), and a DPDT switch form the heart of the point mover. The half-inch hole behind the switch allows lateral adjustment and the smaller countersunk hole at the end is the pivot point. A washer screwed down over the large hole after final adjustment locks the unit in place. The brass extension of the switch handle (Figure 2), is secured with ACC in a 3/16” deep slot cut into the handle.

Installing the Turnout and Controller

I use cork roadbed over plywood for my trackwork, but the installation procedure is similar for other materials. Follow Photos 6–7 to see the process. After locating the turnout on the roadbed and drilling the frog feeder hole, screw the frog wire into the bottom of the turnout as in Photo 2. I first coat the screw tip with some anti-oxidation compound to insure a good, permanent electrical connection with the turnout. You can get this in the electrical department of the same hardware store where you got the aluminum strip.

Photo 6: After locating the turnout on the roadbed, push a short piece of wire through the screw hole in the frog and into the roadbed below. Lift the turnout off and center a large nut over the wire.
Photo 7: Pull the wire out of the nut and drill down through the roadbed and substrate, pressing down hard on the nut as you do so. I use a 3/8-inch drill to get plenty of wiggle room around the frog wire and its screw. Pressure on the nut while drilling keeps the drill bit from lifting the roadbed and getting wood chips under it.

The turnout is thrown with a piece of .025-inch music wire passing down through the roadbed in a 1/16-inch diameter brass tube. The music wire is a fairly loose fit in the tube to reduce friction, and make bending the wire to fit the hole in the throw bar a little less critical. The relationship between point thrower position under the track (which may be dictated by benchwork constraints) and the position you want the control knob to be in for a given position of the turnout, will determine on which side of the throw bar the tube is placed. For example, I standardized my turnouts so the knob is pushed in when the far track is selected, and out when the near track is selected. Once you figure this out, Photo 8 illustrates the installation.

Photo 8: Drill a 1/16-inch hole about half an inch from the appropriate side of your chosen throwbar hole. The brass tube should go from tie-top height to about an inch under the subroadbed below. Most of the spring action in the music wire occurs as twisting torsion inside this tube, so don’t shortchange its length. Bend the music wire to hook into the throwbar hole, drop it through the tube and cut it off about 1 3/8-inch below the bottom of the tube. Then grasp the tube firmly and bend the wire at a right angle as it comes out of the bottom of the tube, aiming it toward where the point mover will be mounted. Pull down on the wire while doing this to keep it from rising out of the throwbar on top. Now you should be able to easily wiggle the wire back and forth and hear the “click-click” of the points moving above.
Photo 9: Components are ready for installation. The wood blocks locate and secure the model airplane control tubing. Figure 3 gives the dimensions of these blocks. Make as many of these component sets as you will need, assembly-line fashion, and then set them aside for quick and easy installation later.
Photo 10: Position the point mover under the layout so the switch end of bracket squarely faces the brass tube, with the end of the switch handle extension about an inch away from the tube. Mark the centers for the pivot and the lock-screw holes and drill 1/16-inch pilot holes. Reposition the point mover with the music wire passing through the end hole in the handle extension. Drive the pivot screw in hard enough to secure the unit while still leaving it movable with effort. Loosely drive in the lock-screw with its washer. Throw the points back and forth with the switch handle, and on top of the layout note how strong the spring pressure is on the points in each position. Pivot the point mover until spring pressure is equal in both positions and securely tighten the pivot and locking screws.

Photo 9 shows the components of the turnout controller ready to install. Photo 10 shows a completed installation and describes the adjustment procedure. Getting a helper to assist with the adjustment can save your knees and back.

Control Linkage

Turnout control is from the edge of the layout by means of the telescoping nylon tubing used by RC airplane hobbyists to operate control surfaces on their planes. See Photo 11 for a sample of the materials available. Photo 12 shows how additional bell-crank components can be used in tight situations.

Photo 11: Radio-controlled airplane hobbyists use components like this in their models. The tubing comes in three or four-foot lengths and includes 2-56 threaded rods and clevises for end connections. The tubing is quite flexible, but of course there is a limit, so experiment to see how much bending can be done in your situation.
Photo 12: In places where the bend is too severe for the tubing, or when connecting a turnout on an upper level to a control knob on a lower fascia, I have found it useful to use bell-crank assemblies, also model airplane components, to eliminate one or more of the right-angle turns difficult situations might require. More aluminum strip and wood blocks support the bell-crank and tubing.
Figure 3. Support blocks made of 1- x 2-inch wood, locate and hold the plastic tubing used to operate the controller. One block is placed near the controller under the turnout and another is located a few inches in from fascia board on the side of the layout. Amount of countersinking needed for mounting screws can vary depending on the length of screws you use.

Unless the tubing run is very short, two wood blocks made of 1- x 2-inch stock secure the outer guide tube. See Figure 3 for the dimensions of these blocks. The hole for the tubing should give a nice tight fit for the tube to keep it from working back and forth on its own, but you still need to be able to push the tubing through it. Again, I recommend mass producing these blocks for convenience later.

Secure one block near the point mover under the turnout. Use just one screw to begin with. Push the outer control tube through the second block that will be placed behind the fascia board. Drill an appropriately placed hole in the fascia board, insert the outer tube through it, and push the far end of the tube through the block near the controller, leaving about an inch of space between it and the hole in the extension handle. Now position the other block a few inches from the back of the fascia board in a way that directs the tubing through the fascia at a right angle, and screw it to the benchwork.

Screw a piece of the 2-56 threaded rod that comes with the tubing into one end of the inner tubing, clip a clevis to the switch handle extension, thread the inner tubing through to the point mover, and screw the threaded rod into the clevis. Leave about half a dozen or so threads visible between the tube and the clevis to allow minor adjustments in cable length later. Tweak the wood block back and forth on its single screw to optimize alignment between the control tubing and the hole in the handle extension, and secure the block with a second screw. Again, refer to Photo 13 to see a completed installation as viewed from below. Photo 14 shows how it looks to the operator.

Photo 13: One tube-support block is placed about two inches away from the point mover connection and the other is at the edge of the layout or a few inches behind the fascia board, so the fascia is not bearing the push-pull stress on the tubing. The gap allows flexibility to correct for small drilling errors. This outer block can be left out if the turnout is so close to the edge of the layout that the inner block is within a few inches of the fascia board, but at least one block must always be used to securely locate the tubing.
Photo 14: After under-layout installation is done, trim the tubing at the fascia board, and install a control knob. Important: Push the inner control tube in at the layout edge first, and then cut off both tubes near the surface with a hobby knife. Then push the inner tubing out again from the back and screw in your control knob, holding the end of the tube with pliers to keep it from turning. Another hobby of mine is collecting antique typewriters, so I happened to have a good selection of discarded typewriter keytops handy. They made ideal push-pull knobs for this application. Other knobs can be easily obtained at your local craft store.

Now all that needs to be done is to make the electrical connections and you are finished. The frog lead goes to one of the center posts on the switch, and the track bus leads go to the side posts. Make sure you have the bus wires going to the proper posts for correct frog polarity before soldering.

Three-Way Stub Turnout

A special adaptation was needed for a hand-laid three-way stub turnout on my layout. This application uses two of the controllers just described. Both controllers are fastened to a 1- x 1/8-inch aluminum strip as a foundation, which is in turn screwed to the underside of the benchwork. The controllers are positioned facing each other so that a brass link can be connected between the handle extensions using the cable clevises as pivot points. The pivot holes in the link bar are two inches apart. The rail movement wire is actuated from the center of this link. When both controllers are thrown in the same direction, either forward or backward, the side tracks are selected. When the controllers are set in opposite directions, the center track is aligned. See Photos 15 and 16 for the details. Wiring is illustrated in Photo 17. With this setup, only one of the two possible settings for the center track will work electrically, but this is just a matter of getting into the habit of using the right combination. A notice on the fascia board is a reminder of the correct setting. See Photo 18.

Photo 15: This hand-laid three-way stub turnout presents a special control situation. Stops on the outside of the side tracks automatically align the movable rails for the diverging routes, while center track alignment is made by fine-tuning the controller positions under the layout. It is important that slop and play in the linkage be minimized for accurate and repeatable center-track alignment. This minimization of play required the use of an intermediate throw bar (running from the control wire to the center of the main throw bar) so changing angles created by movement of the rails would not cause binds in the linkage.
Photo 16: Bottom views of mechanism showing how two controllers regulate the movement of the three-way stub switch. Two controllers face each other with a brass link pivoted between them. Once again, slop in the movable connections needs to be minimized for accurate and repeatable rail alignment. Both controllers in the same position selects for the side tracks, while putting them in opposite positions splits the difference in the throw and aligns the center track. A music wire leading to the throw bar above takes its movement from the center of the brass bar linking the two controllers. One of the end holes in the linking bar is slotted longitudinally to accommodate length changes that occur when the switches are thrown. Only one combination of controller positions for aligning the center track (in my case, left out, right in) will work electrically, but it simply means getting in the habit of using the correct one.
Photo 17: Wiring for the two switches used to control the three-way stub turnout. When properly done, each frog is connected to the needed polarity for the route selected. Again, the center track uses only one of the two possible switch configurations.
Photo 18: Card mounted on fascia instructs guest operators (and reminds me!) on the proper combination of controller positions for three-way stub turnout.

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