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Automatic operation of a model railroad switchback layout.

switchback track plans
Mountain railways often resort to a switchback track plan so their trains can reach a mine or a logging operation. A train shuttles back and forth from one switchback to the next to climb a steep mountain face.
This Azatrax SwitchBack control circuit automates the switchback train. This adds motion and interest for visitors, yet requires no attention from the layout operator.
DC-powered trains are required because the SwitchBack controller circuit changes the train direction by reversing the +/- polarity of the track power.
A train detector (sold separately) is needed at each track end point. Any device that closes an electrical contact, such as any Azatrax infrared train detector or a magnetic reed switch, can be used. The train will pause at each detector, then will reverse direction and continue up or down the grade.

  • Delay time at end points is user selectable from seven to 36 seconds.
  • Acceleration and braking effect is user adjustable.

The SwitchBack controller can control up to four track switches. The five possible track plans are shown at the right.
One SwitchMaster™ or Tortoise™ low current switch machine is required to operate each track switch. Cobalt™ switch machines are not recommended as they require a higher voltage than the SwitchBack controller provides.
switchback control circuit
For other automated back-and-forth layouts click here.
Automated SwitchBack Control Circuit
New version expected to be available May 2017.

Out of
Infrared train detectors  
Tortoise™ slow motion switch machine
• One required for each track switch


Accessory power supply, PS1206
• Regulated 12vdc, 600mA, slim plug-in
• One supply can power the switchback controller, detectors and four switch machines.



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