Reverse Loop problem


Tom Anderson
 

Good Morning,

 

          I have a reverse loop (picture uploaded) that is not working correctly.

 

          I am using a Digitrax PM42 with district 2 setup as a reversing loop.

 

          The train is traveling right to left on the diagram. If it attempts to enter the loop at Switch #2, the layout shorts out. If I attempt to enter the loop from Switch #1, the train proceeds normally and exits back out through Switch #2 normally.

 

          Not sure what I have wrong. Any help would be appreciated.

 

Tom Anderson

 

 

Tom Anderson

Business Information Systems

P.O. Box 160396

Boiling Springs, SC  29316

 

(864) 621-8607

 


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Jim Betz
 

Tom,

  Your layout wiring is fine - assuming no closed gaps for the reversing loop.
I'm sorry to say that the most likely source of the problem is the use of the PM42.
The PM42s were designed a -long- time ago and do not do well with 'modern'
DCC locos ... especially any with sound.  Or with a lighted passenger train.
  So even if the reverse loop was working correctly I'd be recommending you
use a PSX-AR to power that loop.  The power to the PSX-AR should be fed
directly from the track bus (i.e. "booster power") and not from the output of the
PM42.
  If it were me I'd also replace the PM42 entirely and replace it with a standard
PSX (or more if there are other power districts).
                                                                                               - Jim in the PNW


Tim
 

I would use a DPDT relay with a 12V coil powered by the switch machine contacts for this. Assuming that the two turnouts are pretty close together, I'd connect it to turnout 1 so that it energized when turnout 1 is thrown (lined for the loop). I don't recommend using the contacts directly because they are often very slow acting and of limited current capacity. You can get a relay rated for 10 A for less than $10.

Tim Rumph
Lancaster, SC


Tom Anderson
 

Thanks Jim. 


On Mar 15, 2022, at 10:15 AM, Jim Betz <jimbetz@...> wrote:

Tom,

  Your layout wiring is fine - assuming no closed gaps for the reversing loop.
I'm sorry to say that the most likely source of the problem is the use of the PM42.
The PM42s were designed a -long- time ago and do not do well with 'modern'
DCC locos ... especially any with sound.  Or with a lighted passenger train.
  So even if the reverse loop was working correctly I'd be recommending you
use a PSX-AR to power that loop.  The power to the PSX-AR should be fed
directly from the track bus (i.e. "booster power") and not from the output of the
PM42.
  If it were me I'd also replace the PM42 entirely and replace it with a standard
PSX (or more if there are other power districts).
                                                                                               - Jim in the PNW

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