Reverse Loop Question

Wayne Swearingen

Looking at the photo's there should almost be a groups page dedicated to reverse loops! 

We're in the process of converting to DCC and in deliberations on how best to wire/block the loops we have. There is only one mainline running around the loop but there are staging tracks off of it. I was planning to detect occupancy on the mainline but not the staging. If we do detect staging the BDL168 will work with one zone-section setup for auto reverse, I'll have three sets of tracks to detect and the fourth can just die or possibly be used elsewhere within the loop if need be, may splitting the mainline into two detected zones. If we just do the mainline I'll need to purchase a BXPA1 unit to detect it as one. 

What do the experts here say as far as gapping & setting up the reverse loop?

Don Vollrath

If your photo is accurate, there are 3 relatively independent reversing loops. The Red outside loop and each of the 2 Green indicated loops. AND a possible wye toward the center (the track sketch paths are not perfectly clear.) The yellow marking for planned track gaps would end up with the green reversing loops coupled inside the red loop. I would move the gaps for the Red outside loop to be so that only that track loop is isolated. Then place other gaps to isolate each of the other green loops from each other where they break apart from the turnout exits. This move would best utilize 3  independent A-R units, each powered directly from the mainline feeder bus. 2 separate (green) loops may not be necessary depending on the actual length and planned movement restriction of trains on those staging tracks. 
In this manner you can add independent track occupancy detection on leads to these 3 areas after each of the A-R units if desired.

The wye in the center also needs to be carefully looked at for reversing issues. It creates a very short reversing area where a loco or train can enter from the main line, go through the wye and return to the mainline in the opposite direction. ie - a 4th reversing loop independent of all others. This in itself may require yet another A-R unit with track gaps placed to prevent one A-R area from being adjacent to another. Knowing or restricting train length through this path will be paramount for success 

Can you quantify any restricted movements for future trains at this end of the layout?