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.
Thanks
wdcrvr
Can you email the drawing and we can post it for you?
Rich
Alton Junction
Here is the track diagram that wdcrvr referred to in his post.
wdcrvr,
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.
Good luck.
I personally would make the gaps after the crossovers.
It would be two less gaps to cut. (Eliminates crossover gaps)
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
DigitalGriffin I personally would make the gaps after the crossovers. It would be two less gaps to cut. (Eliminates crossover gaps)
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.
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.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
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.
Does this help?
As I just replied to Randy. The track to the left just runs in a continuous loop. Therefore, a dogbone with just one crossover.
Hopefully this will clear up the problem.
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.
Jeff But it's a dry heat!
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.
Modeling the Cleveland and Pittsburgh during the PennCentral era starting on the Cleveland lakefront and ending in Mingo junction
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.
rrinker 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. --Randy
Randy,
Like this? Yep, that will work. Of course, you have to be careful to put the correct feeder wire on each rail to keep those parallel tracks in phase.
richhotrain rrinker: 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. --Randy Randy, Like this? Yep, that will work. Of course, you have to be careful to put the correct feeder wire on each rail to keep those parallel tracks in phase. Rich
rrinker: 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. --Randy
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.
BIG JERR richhotrain: rrinker: 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. --Randy Randy, Like this? Yep, that will work. Of course, you have to be careful to put the correct feeder wire on each rail to keep those parallel tracks in phase. Rich 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.
richhotrain: rrinker: 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. --Randy Randy, Like this? Yep, that will work. Of course, you have to be careful to put the correct feeder wire on each rail to keep those parallel tracks in phase. Rich
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.
Sure, the only restriction is the one that is always there. The gaps on both ends of the loop can't be bridged at the same time. But that's true in any case, no matter how you implement it, and doesn't have anything to do with how many trains are in the loop.
I can see how this will work, however, I only have ONE crossover, not two. The tracks leading off to the left in my original diagram form a simple loop.
wdcrvr I can see how this will work, however, I only have ONE crossover, not two. The tracks leading off to the left in my original diagram form a simple loop. wdcrvr
For now! You know you are going to want to turn the train back around.....
Keeping the feeders straight is easy - use two different colors. I use white and red, matches my white and red bus wire. White instead of black since in the shadows it's clearly different than red whereas red and black can start to lookt he same. My layout is around the walls, so I have a 'front' and a 'rear' - front being where you stand and rear being against the walls. Red WIre Rear. Haven't messed one up yet.
I did that because you indicated that a crossover on the left side was contemplated for the future.
If your layout is simply a dogbone with a single crossover in the middle, then go back to my first drawing where there is a top and bottom diagram in red and blue. The top diagram would apply to a simple dogbone with a single crossover in the middle
OK. I am amazed that you guys haven't given up on me yet. Let me try to explain my confusion with the diagram as you haave set it up. As a train comes from the left on the lower track in the drawing it enters into the reversing section as it crosses the gaps before it gets to the crossover. No problem there. Now if it continues straight thru the turnout it goes around the loop and now comes from the left on the upper track and takes a left onto the turnout to make the crossover. Good. When it crosses the gap in the crossover it meets a polarity problem. Obvious. So the ar1 flips the polarity in the reversing section, right? However, SINCE BOTH SIDES OF THE GAP IN THE CROSSOVER ARE CONTAINED WITHIN THE REVERSING SECTION, you will be trying to flip both sides of the crossover at the same time. How would you ever get both sides of the gap in the turnover to ever match? It looks physically impossible to me. You would come to the same situation if you brought the engine in from the left on the lower track and tried to go left at the turnout to make the crossover before you entered the loop.
However, it seems to me that if the gaps in the lower track were moved to the right in the drawing, past the point where the turnout for the crossover is, then everything would work right. As you crossed the gaps in the bottom of the drawing there would initially be no need for the AR1 to change anything. Then when you made the turn from the top track into the crossover, the AR1 would reverse the loop and because the other side of the gap in the crossover is not in the reversing section, it would match and you would continue on. If you came in from the left on the bottom track and took the turn onto the crossover, as you hit the gap in the crossover you would just then be entering the reverse section. The AR1 would flip the polarity in the reverse section and you would continue thru the upper portion of the loop. As you came down and around to the left on the bottom track you would come to the gaps (before you reach the turnout for the crossover, not after) and the AR1 would then flip the polarity in the reverse section to once again match the bottom track and you would continue on.
My explanation above makes complete sense to me but maybe my brain is in a reverse loop and just doesn't know it.
Please extend your amazing patience just a little bit more and tell me why I am wrong. Maybe I just don't understand how the AR1 actually works? I feel like a real dummy here, but I have never met a concept before this that I could not eventually get ahold of. So I am determined to understand this process.
And I do not want to entertain the idea of having another crossover at any point. I will turn trains around at the other end of the layout by having a line go off to a turning wye or a turntable. So please disregard that in your answer to my questions.
I am almost afraid to send this post because I can just picture you guys pulling your hair out and wanting to get your hands around my neck. So, maybe it's a good thing that we don't live near each other. I will understand if you want to just give up on me.
wdcrvr (I know I'm not crazy, just confused)
You are not crazy, I am. My apologies. I posted an erroneous schematic the first time, and you can see the error on the bottom diagram in that drawing. I had corrected it early on but posted the wrong drawing.
You are correct. The gaps on the bottom track should be to the right of the turnout, not the left.
Here is a corrected drawing, and you can see the effect of the AR1 flipping the polarity in the reversing section to match the track outside of the reversing section in the bottom diagram.
Thanks for not giving up on me.
I feel confident to move ahead now.