I am building a layout similar to #48 in 101 Layouts book. There is a point where the track makes a loop and then runs parallel to the track that came into the loop. At a point in these parallel tracks, running in opposite direction there is a crossover that allows one to either continue on the return track or switch over and return on the track you came from. So I have figured out that this constitutes a reversing loop but I am not sure where to put my gaps. I have sketched out what I think I should do but don’t know how to attach the drawing to this message. Basically, there are two left hand turnouts that come together to make the crossover. I think I need to put in three sets of gaps. One set of gaps would be where the two turnouts meet in the middle of the crossover. The other two sets would be at the end of each of the turnouts. This would mean that the turnout leading into the reverse loop would not be included in the reversing section and the turnout leading out of the reverse loop would be included in the reverse loop. The AR1 wouold then be wired so that two wires would lead out to the reversing section and two wires would lead to the non-reversing part of the track.
Yes, I just fell off the turnip truck and need lots of guidance. I really appreciate the patience of all you wonderful people. If not for this forum I don’t know where I would go to learn anything about MRR.
In the diagram that follows, the drawing at the top of the diagram shows the reverse polarity where the two turnouts meet to form the crossover. The circles indicate the placement of the rail gaps to create a “reversing section” that will be controlled by the AR1.
The drawing on the bottom of the diagram shows the effect of tripping the AR1 as an engine or consist crosses from one track to another from left to right or, for that matter, from right to left. The polarities are reversed and matched so that the train can proceed into the loop, or out of the loop, without shorting the layout.
Everything to the right of the gaps on the parallel tracks is the “reversing section”. All feeder wires within the reversing section should be routed into the output side of the AR1. A pair of feeders from the main bus wires should be connected to the input side of the AR1.
Yep, you could do that as long as you are careful about keeps those polarities in phase on the two parallel tracks. Otherwise, you will create a short in the middle of the crossover.
Rich
Edit Note: This is what DigitalGriffin is suggesting:
OK. I realize I am the one asking for help so I feel a little bad in that what you are suggesting does not look like it woould work. Shouldn’t the gaps that you show in the track at the bottom of the loop be moved to the right on the drawing so that they are past the turnout? When I try to visualize how this will work it just doesn’t seem right. This layout shows the gaps in the crossover contained within the reversing section. Doesn’t that cause a problem? Please forgive me but I am still confused with this drawing.
Ouch. This is even more confusing to me. The tracksd leading off to the left in the drawing go to the rest of the layout and are connected in a contnuous loop. Therefore the polarity shown in this drawing could never be. Am I right? I really feel bad about questioning what you guys are telling me but it just isn’t making sense to me yet, or maybe I am not really explaining the situation properly. The way I keep looking at this I see a need to put gaps in the middle of the crossover and then gap the lower track after it passes the crossover. And gap the upper track so that the upper half of the crossover is included in the reversing section. There would be three entry points into the reversing section. 1. At the midpoint of the crossover 2. Along the bottom track just past the crossover. 3. At the top track to the left of the crossover. The reversing section would include the loop and only one half of the crossover. Is this wrong? Am I just too dense to figure this out?
Please be patient with me. If I try to do these various methods do I risk destroying my AR1 if I do the wrong thing or can I feel safe in trying the “process of elimination” until I get it right?
Wait - the other side of the layout, the part not shown off to the left, is just a mirror image of this? In other words, you have a dogbone-shaped layout with some crossovers on the narrow part? There are several ways to handle this but the easiest is to use two autoreversers and set each one up the way DigitalGriffin mentioned, isolate the loop on each end and connect each one to an autoreverser. Unless you only ever run one train and it will never be in both loops at the same time, in which case you might be able to get away with a single reverser.
Perhaps the problem is not knowing what is to the left of the diagram. In other words, what is the track configuration to the left beyond the crossover.
Are the two parallel tracks leading up to the crossover wired in phase? In other words, if your feeder wires were colored red and blue, which rail on each parallel track has a blue feeder wire and which rail on each parallel track has a red feeder wire?
The track to the left is a continuous loop. But there is not another crossover. At least not yet. So I guess you would call it a dog bone with one crossover.
If it’s an oval (conceptually) with just this crossover, than Rich’s first drawing will do the trick, and the second drawing won’t work, since the crossover needs to be inside the reversing section.
Don’t get where the electrical reversing section is confused with where the physical reversing section is, they can be quite different.
Same thing basically holds then, isolate each loop, and put an autoreverser on each one. The parallel tracks in the middle, just make sure the bus wires are int he right order so the polarities match. You cna have as many crossovers as you want, and any number of sidings off the parallel tracks without worry.
Having gone through this recently myself and still working on the fine tuning of it I suggest drawing out a straight line diagram of the whole track plan. Then get some colored pencils, pick a spot that looks like it would allow the most track to run off the main bus and start color coding each rail on either side of the straight line. When colors collide you have a reversing section. Redraw that spot so you can conectrate on where the gaps need to be so that you avoid having colors collide and use a 3rd color to indicate what needs to be reversing.
See my thread for examples of the diagrams and color coding. My track plan is more complicated than yours but you should still get the idea.
Since the layout has a continuous loop on both ends of two parallel tracks 9i.e., a dogbone), the first diagram is accurate. I have attached that diagram here once again, However, I have also added the left side of the layout and shaded it to make it easier, hopefully, to understand.
The reason that the crossover needs to be gapped between the two turnovers is because of the reverse polarity where the two turnouts meet.
As Randy pointed out, in this dogbone arrangement, you are going to need a second auto reverser because you effectively have two reversing sections.
If you isolate the two loops to the left and right of the crossovers, respectively, you will NOT need to gap the crossovers - the ‘front’ and ‘rear’ mains would have their rails wired the same, not reversed. Blue-Red Blue-Red not Blue-Red Red-Blue as drawn.
Depending on the turnouts used - Atlas would not require gaps on crossovers.But that has nothign to do with the loops themselves.
An added benefit of doing it this was is that you can add or subtract crossovers in the center section with out worrying about whether you’ve done anything to the reversing sections.
this is a great way to do it ,but CAN muti train operations take place inside the loop (reversing area) or is it only one train at a time inside that area ? J.W.
