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Reply to "Video, Z-Stuff DZ-1012 Block Detector Controls Two O-Gauge Trains On 1 Mainline"

BOB WALKER posted:

Z-Stuff IR detectors were used to accomplish two trains on the same loop in my October2007 article in CTT. The IR detectors sensed the train location and controlled the power to designated insulated blocks. 

Hi Bob -

  • Thanks for posting a copy of that automatic control article.
  • FYI:  I have enjoyed reading some of your great CTT articles and viewing some of your videos, but that particular article I was not aware of it.


  • I would claim the method shown in this new Video #668 video using the newer DZ-1012 detector, is a bit SIMPLER.   (You might not agree with this claim.  Also, the DZ-1012 was not available until 2017.)
  • In this video #668, we used just ONE detector, ONE relay, and ONE isolated "stop block".
  • Also, we can run just ONE train (manual operation, when not running both trains) in the forward direction -- without having to add any electrical switches.

In the system you show in the 2007 article, I think that system is more prototypical -- and also more "fail-safe" -- because I believe each train is protected by a block. It would be interesting to see a VIDEO of that system operating.

Also, DZ-1012 May Run MORE Than 2 Trains

With this DZ-1012 type of  system shown in the video, you can sometimes run MORE than 2 trains -- IF you have a longer mainline, and IF the locos run somewhat similar speeds.


  • In the 1992 videotape V92902-5D, I did a demo using the "APS Electric Eye" (which functioned similar to the DZ-1012.
  • Like the DZ-1012, the APS Electric Eye had one normally-closed contact, one normally-open contact, and an adjustable time delay.
  • The video shows FOUR LGB trains being separated, and operated by just 1 Automatic Block.
  • There's an excerpt of that video shown in Part 2 of Video #668 at about the 18 minute point, which can be viewed with this link: .  The complete video V92902-5D can be viewed at .
Last edited by James Ingram
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