Turnout Motors - Also known as Point Motors or Switch Machines are a mechanical device which electrically controls a turnout's alignment. There are several types, slow motion machines, such Tortoise by Circuitron, the Cobalt series by DCC Concepts & soleniod types by Peco & Hornby.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 switch points close, the motor stalls and holds them in position.
A 3-wire solenoid has two coils (twin coil) and an iron slug (the armature) at their core. By energizing one coil, the armature 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. The armature is connected to a rod to transfer the motion. This connects to a mechanism which allows the position to be held (latched) until changed. This mechanism, usually a lever, allows the throw of the armature's motion to be adapted to a more useable form. Contacts are often provided, which can be used to control the frog.
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.