The Reversing Loop That Didn't

Been away from the blog for awhile but had a fairly productive weekend adding power feeders, buss bars under the layout and basically wiring up section after section on the lower portion of the layout.  I had the reversing loop wired for awhile and added in the Digitrax AR1 Reversing Module this weekend.  It seemed like a simple plug and play, until it didn't work at all.  Hmmmm....  It was supposed to be a fairly simple plug and play.  Essentially, this is a compute module that senses the "short" caused when the loco wheels cross into the reversing loop and automatically adjust the power to match the leg where the loco entered.  In DC layouts, there is a manual switch that controls the reverse.  Automatic is much nicer. Well, I turned to my never disappoint me resource of N Scale Net DCC Forum for some help.

I posted my layout schematic (which will be used on my control panel) along with some labels showing where my "A" circuit was located:

I had several suggestions for adjustments to the AR1 and then a User by the name of Heiko made a startling revelation:  "Apart from your AR trouble, which you should solve anyway: The purple section is not your reversing section. The section where you will connect A to B and B to A is the horizontal blue track you reach when you go counter-clockwise through your purple section - or, if you want, you can add the purple track to the part switching it's polarity, but including the T/O between the purple and the horizontal blue track.  The purple section is "just" a siding to the black section it follows. So the AR should not be required at all for that section.

WOW!!!!  He was right.  I never realized when I converted the Atlas DC layout to my own layout, the area Atlas called the Reversing Loop - really was not working that way.  I posted some replies and settled on the following rework of the layout:

I had also read (on the Digitrax site) that it's a bad idea to have the insulated gaps of a reversing loop at the end of a turnout.  Well, I had my insulating gaps at the ends of a turn out on both ends of the reversing loop.  The rework shown above eliminated that issue and also made a true reversing loop.  The change added some length to the reversing loop, which translates into a longer train capacity.  The longest train on your layout is limited to the length of the reversing loop.

The downside of this rework meant tearing up track that was nailed down and roadbed that was glued down.  Had to do what I had to do.  It was a couple nights of work to rework.  Once I relaid the new segment of roadbed and laid the new track in, I had to go back and check all the track feeders.  So far, so good.  The moment of truth came when I wired up the AR1 module.  I powered up the layout and the first test of the reversing loop was a complete success!!!!  I had a few folks ask to see a video of the reversing loop in action so here it is:

You may notice that the loco has a millisecond of hesitation as it crosses the reversing loop insulated gap.  While standing at the layout, you can actually hear the AR1 make a click sound as the loco keeps right on trucking.

Another very valuable, and somewhat painful, lesson learned.......