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Digitrax PM42 as AutoReverser

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  • Member since
    June 2021
  • 2 posts
Digitrax PM42 as AutoReverser
Posted by fldave on Thursday, June 24, 2021 7:20 AM

After 30 years I am getting back into the hobby!

I have settled on DigiTrax and have picked up a few components already.  I have a basic double mainline figure 8 layout and a reversing section and a couple of crossovers.  I am using a PM42 for Power Management and a BDL168 for block detection.

I have read a number of other posts about using the PM42 for the reversing section vs something like an AR1.   I am trying to determine if it make more sense to insert an AR1 between the PM42 and BDL168 to hande the reversing section.  The reversing section will have multiple blocks as t has some side tracks.

Thanks, Dave

  • Member since
    April 2008
  • 113 posts
Posted by AlienKing on Thursday, June 24, 2021 12:38 PM

I'm using a couple of PM42s with a mix of regular and reversing sections.  They work well enough for me. 

 

It's easy enough to change the settings, so you might as well test it out to see if it handles your needs before buying anything else.

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,483 posts
Posted by MisterBeasley on Thursday, June 24, 2021 12:54 PM

Hi and welcome to the forums!  Welcome

 Be advised that all new members are under moderation for a few post (small number) so you won't see your post right away.  It's normal, and it passes quickly.

As a former DC user myself, it took me a while to break the habit of blocks and sidings with kill switches when I went to DCC.  Since you control engines individually, you don't need a dead track for them when running another engine.  Just set the speed to zero and the engine will stay put.  You may want a dead siding to shut off the lights on passenger cars.

It takes an iron man to play with a toy iron horse. 

  • Member since
    June 2004
  • From: From Golden, CO living in Puyallup (Seattle), WA
  • 751 posts
Posted by Renegade1c on Thursday, June 24, 2021 1:51 PM

To answer you question, if you do use an AR-1 instead of using the PM-42 for auto reversing, in needs to between the PM-42 an the BDL 168. If its after the BDL-168 it will always show that block as occupied because the AR-1 is drawing current off that block. its not much current but enough for the block detector to show occupied. Also if you plan to have multiple detection blocks in the Auto reversing section it is necessary to place the AR-1 between PM-42 and BDL 168. 

Treat each device as what it was intended to do. Even though Digitrax designed in extra features its not always the best use of the device. When the PM-42 is setup for autoreversing it no longer works as a circuit breaker. 

Slightly OT. Should you choose to continue to use the PM42's and BDL 168's, I highly recommend the Acculites Breakout boards found here: http://acculites.com/index.php?main_page=index&cPath=100 they make wiring everything so much easier on those devices. I used them on my SE8c signal decoders. 

I happen to prefer DCC specialties PSX circuit breakers (and auto reversers/circuit breakers). They have worked better for me especially with sound units. 

One of the reasons I ditched the PM-42 and went with the PSX is that they make a circuit breaker that is also an autoreverser (PSX-AR) and is designed to do that. The other main reason is that they are completely solid state, no mechanical relay to fail and much easier to wire (two wires in, two wires out) and don't require external power. They are a bit pricey but are complete interoperable with Digitrax systems. They can also be daisy chained together if you need mutiple blocks. 

One of the beautiful things about Digitrax is the availability of 3rd party vendors. Companies such as RR-CirKits and Team digital offer devices that are fully loconet (Digitrax) compatible but do it better than Digitrax does. Tam Valley Depot is another vendor that is loconet compatible should you choose to use servos for turnout controls. 

Hope this helps.

 

 

 

 


Colorado Front Range Railroad: 
http://www.coloradofrontrangerr.com/

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  • Member since
    August 2020
  • 84 posts
Posted by MrMe on Thursday, June 24, 2021 10:09 PM

Do yourself a favor and replace the PM42 and the BDL168 with a BXP88, and get a BXPA1 instead of an AR1.

You'll get the same (actually more) functionality with one less device, eliminate the older relay-based technology, and gain the ability to upgrade the firmware for future enhancements/fixes.

  • Member since
    January 2021
  • 32 posts
Posted by Oldngrey on Thursday, June 24, 2021 11:39 PM

A very good answer Renegade1c

The reason I chose the PSX-AR was a YouTube video showing a sound loco crossing a reversing loop boundary. The PSX-AR was seamless, the PM-42 or AR-1 had a distinct interruption in the sound.

I also use a PSX-3 for my power districts. I find using relays (Digitrax products) to control track power to be too slow for sound equipped locos.

Otherwise I have a Digitrax system.

  • Member since
    June 2021
  • 2 posts
Posted by fldave on Friday, June 25, 2021 6:15 AM

Thanks everyone!

I will have a look at the PSX series products.  For my first segments I will go with what I have and put the AR1 between the PM42 and BDL168.

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