Tortoise™ Switch Machine
Used with permission from Circuitron.

Turnouts:
Since the polarity of the stock rails with reference to the Tortoise™ will vary depending upon which way the Tortoise™ is mounted, it is best to use the terminal block as shown. If a short circuit occurs in your track power circuit, immediately remove power and reverse the connections to circuit board positions 2 & 3. If all your Tortoises™ are mounted facing the same way, you can eliminate the terminal block after you have determined the proper connections. With Shinohara™ brand turnouts, we recommend bending the small contacts protruding from the points in the vicinity of the throwbar down and out of the way so that they do not contact the stock rails. If you do not do this, a short circuit may occur if the Tortoise™ contacts switch before the Shinohara™ contacts break their connection with the stock rails. With Peco™ brand turnouts, it is best to remove the stock over-center spring so that the points move freely. The Tortoise™ spring wire will provide optimal point tension without the Peco™ spring and short circuits as described above will be eliminated.

Signals & Relays:
Since the internal Tortoise™ switch contacts are completely isolated, they may be used for powering AC or DC circuits. The drawing above shows a typical installation of a trackside block signal. Power to the signal is provided from the layout signal supply, typically 12-16 volts AC. Note that if the signal is a Light Emitting Diode (LED) type, a DC power source MUST be used. In addition, the current limiting resistor in the “common” lead must also be included to prevent burnout of the signal. See the signal manufacturer’s recommendations for resistor values. If the wrong lamp lights after wiring, interchange the connections to circuit board positions 6 & 7.

When heavy currents are to be switched by the Tortoise™ , we recommend driving a relay from the auxiliary contacts. The relay coil would be wired exactly like the signal and would connect to either position 6 OR 7, but not both. Select a relay with a coil compatible with your power supply. The current limiting resistor would not be used with the relay coil.

USING THE Tortoise™ WITH PECO TURNOUTS

The Tortoise™ Slow Motion Switch Machine provides constant point tension by nature of the constantly powered stall action and the spring wire transmitting the motion to the points. Some brands of turnouts such as Peco have an internal over-center spring which causes a snap action throw. Although this is desireable when used with twin-coil switch machines, it defeats the purpose of the slow, smooth action the Tortoise™ is capable of. In some cases, the tension of the turnout spring is greater than the force available from the stock Tortoise™ wire, and although the Tortoise™ will make its complete throw under the layout, nothing happens at the points.

We recommend that you remove the stock spring from the Peco turnout. This is easily accomplished if the turnout is not yet mounted, but should be able to be achieved with a little more difficulty even if the turnout is fastened down. Once the spring is removed, check for free action of the points. When the Tortoise™ is installed, the system should operate smoothly and provide positive spring tension at each end of the throw.

If you do not want to modify your Peco turnouts, or if you have one mounted inside a tunnel or other inaccessible location, you can still use the Tortoise™ by substituting a heavier gauge spring wire. .032” diameter will usually work well. You will need to enlarge the wire hole in the throwarm following the instructions supplied with the Tortoise™ . If the Peco spring is left intact, we do not recommend using the internal contacts on the Tortoise™ to power the points and/or frog. Since the point movement will occur when the spring wire force exceeds the Peco spring force, it is not likely that the two will occur exactly at the center point of the throw, and the possibility of a momentary short circuit then exists.

Wiring Panel LEDs in Series with the Tortoise™ Switch Machine

The Tortoise™, the Tortoise™ Logo and the Tortoise™ graphic are trademarks of Circuitron, Inc. of Romeoville, Il. They and all photos of the Tortoise™ are used with permission.

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