A motor (or switch machine) that is usually connected to a stationary decoder to control a turnout.
Turnout control in the world of Digital Command Control is a way to control turnouts (or turnout motors/switch machine) through DCC commands. Typically, turnout motors need to be powered though a stationary decoder controlled by commands from your DCC system. Various manufacturers have various solutions. There are also several motor types to make things even more complicated.
- 1 What is a Turnout Motor
- 2 Controlling Turnout Motors
- 3 Wiring Stationary Decoders
- 4 Power Routing with Switch Machines
What is a Turnout Motor
A Turnout Motor or Switch Machine is a mechanical device which electrically controls a set of switch points. There are several types, slow motion machines, such as the pictured Tortoise by Circuitron, soleniod types, and motor driven screw types.
- A slow motion machine uses a stall motor with large ratio gearing. The motor is constantly energized, drawing very little current when stalled. When the points close, the motor stalls and holds them in position.
- A 3-wire solenoid has two coils and an iron slug at their core. By energizing one coil, the slug is pulled into the coil. The slug is connected to a mechanism which is connected to the switch. The coil is only energized momentarily, as it will overheat and burn out if continuously energized.
- A 2-wire solenoid has one coil and a permanent magnet at its core. By energizing the coil with DC current, the magnet is pulled one way. By reversing the DC polarity, the magnet is pulled the other way. The magnet is connected to a mechanism which is connected to the switch. The coil is only energized momentarily, as it will overheat and burn out if continuously energized.
- A limit-switch DC motor type has a can motor with gearing to operate a push-pull actuator. The gearing can be regular gears or a screw (or threaded rod) connected to its drive shaft. For the screw-type, a nut is threaded onto the screw. As the motor turns, the nut moves along the screw. A mechanism connected to the nut is used to actuate the points. The motor is turned off by internal limit switches when the motion required is completed.
- A rotating solenoid has one coil and a rotating permanent magnet at its core which turns a rack and pinion style gear and moves the turnout actuator. This relies on a half-wave rectified AC power source. Each half cycle of the AC power gives the magnet a kick in one direction of rotation and its momentum carries it round for the other half cycle. Reversing the polarity of the rectification, reverses the direction of spin and the actuator moves the other way.
- Radio Control Servos can also be used as turnout motors. Special DCC stationary decoders are available with servo drive outputs.
The solenoid types make a loud noise or snap when actuated.
If you plan to use PECO turnouts on your layout with a turnout motor, you must remove the spring which locks the point rails in place. PECO has published information on the web on how to do that. You can also remove the spring after the turnout is installed, should that become necessary.
List of Various Turnout Motors
|Type||Manufacturer||Model||Accessory Switches||Mounting Type||Notes|
|Slow Motion||Circuitron||Tortoise||2 SPDT||Underside||Edge Connector: EDAC 306-010-500-102|
|DCCconcepts||Cobalt||2 SPDT||Underside||Optional AD1 integrated DCC decoder.|
|Twin Coil||Atlas||"Snap-Switch" Turnouts||None||Integrated||Turnouts with integrated, side mounted motors|
|52, 53||Side||Left and right motors for Atlas manual HO Code 100 turnouts|
|Hornby||PR8014||None||Underside||Surface mount with R8015.|
|PR8243||Side||For use only with Hornby turnouts|
|Peco||PL10||None||Underside||Surface mount with PL12.|
|PM-4||1 SPDT||Self-latching version|
|Single Coil||Kato||All N Scale Turnouts||None||Integrated||Turnouts with motors integrated into base|
|Most HO Scale Turnouts|
|2-503, 2-504||None||Side||For HO Turnouts: 2-840 and 2-841|
|Limit-switch DC motor||Aristo-Craft||11299||1 SPDT||Side||For G scale use|
|Fulgurex||2 SPDT||Surface||Can be mounted underneath to the side.
2 Additional SDPT used as internal limit switches.
|Rotating Solenoid||LGB||12010||None||Side||For G scale use|
|Servo||Tam Valley Depot||SSD001||None||Under||SWR001 available for mounting servo|
Controlling Turnout Motors
Below is a selection of stationary decoders which can handle turnout motors, broken down by manufacturer.
The products listed below are capable of handling turnout motors. However, most products are capable of other tasks such as block detection, push button control, etc. Please see the various manufacturers products pages and manuals for further details.
See Digitrax Products page for full details on Digitrax's products.
As these are Digitrax products, they may also be LocoNet devices.
- DS64 - Controls snap and slow motors. Operate your turnouts directly through any DCC system that has turnout control.
- DS44 - Basic quad stationary decoder for slow motion turnout machines
- Cheapest per turnout, but operates only via throttle commands (and/or computer).
- DS51K1 - Stationary decoder for single kato unitrack turnouts
- DS52 - Dual stationary decoder for bi-polar, snap switches, or slow motion machines
- DS54 - Quad stationary decoder for snap switches or slow motion machines. Has 4 outputs & 8 inputs which be used for positive feedback of switch position, or other uses.
- Older brother to the DS64.
- DM1 - DC motor adapter for use with DS54
- 4 DC Outputs with common positive
- Momentary (0.1 to 15 seconds), Continuous and Flashing (4 to 0.5 Hz) options
- Always programmed to a group of 4 turnout addresses. e.g. 1-4, 5-8, 9-12
- Can use DCC track power or external supply
LS100 and LS110 are identical except the LS100 supports the Lenz RS Feedback Bus
- 6 AC Outputs for twin-coil snap action
- Motorized switch machine like KATO Unitrack turnouts can be used with simple addition of 2 diodes.
- Each output can be given an individual 'Turnout address'
- Outputs can be set to be on for 0.1 to 10 seconds
- Needs external AC supply - Max 16 V (Use a transformer LESS than 45VA or add a 10Ω resistor)
Wiring Stationary Decoders
Hints, tips, and suggestions on wiring stationary decoders for use with turnout control.
Use A Separate Booster or Bus for Control
Or at least a separate bus from a power management device for controlling your turnouts with DCC stationary decoders. The reason is simple: If the stationary decoder is controlled by your track bus, and the movement of the turnout shorts out your track, the movement of the turnout will stop. When power is restored to the track, the short will cause immediate shutdown of the track bus again. Because the turnout motion has stopped, the short will never clear itself. If the turnout was powered by a separate bus, then there would be a temporary short on the track, but power would automatically be restored once the short clears.
For example, use LocoNet or another bus for control with a separate power source, so track bus problems don't cause a feedback loop when a turnout causes a short.
Don't power the stationary decoder from the track bus, and if possible, do not use the track bus for control signals. DCC power is costly, a simple power supply is a cheap source for power.
Keep in mind, that any bus lengths over 30' feet should be twisted and bus ends terminated. Please see the track wiring pages for details, and your owners manuals for wiring and termination recommendations.
Power Routing with Switch Machines
Switch machines can have accessory contacts for controlling signals and routing power to the frog. Maually operated ground throws may also have contacts that can be used for that purpose.