I am wanting to run a 5 x 9 set up very similar to the one below. I showed a friend who has a track and he questioned if the “lollypop” style loop which can change your train’s direction from clockwise to counter clockwise would cause a short as the positive side of the rail suddenly became the negative.
Sure enough I hooked up a primitive trial and it did.
Having seen similar designs I figure there is something simple like ordering a special switch or cutting a connector I am missing. What is it?
If you don’t know the answer, just say so!!! He asked for help not what books to buy!!! Now the answer is there are a few ways but the best way will depend on whether you are running dc or dcc. In either case you will need to isolate the loop and can be as simple as a dpdt toggle connected to the loop.
My set up is DC. Now that I have the correct phrasing I am looking at a few options to make it work. Do auto reversing modules work with DC? Automatic sounds nice although the simplest answer would be to isolate and hook another power pack up to it.
besides being rude, if you don’t know or if you are not willing to give all the needed information, keep your mouth shut. Half information is probably more damaging then no information at all. For some issues it might be better to consult a book then haphazardly gathered partial information from the web. Good information might require drawings and thorough explanation; a bit to much for fast media.
Hi gentlemen,
It is unclear what the loop is Rrebel are referring to. You will have to gap the reversing track at the two sides. Wiring it the old way for DC you will need two DPDT switches (double pole, double throw).
Both wires from the reversing track and both from the “normal” track need to go to a DPDT-switch before you connect them with the power-pack. Yes indeed, a book could be a great help, especially a diagram how to wire the dpdt-switches. With DPDT-switches you have basically 3 positions; In the middle no connection is made at all with the tracks, consider it as an OFF-Switch. To one side the polarity is “normal” to the other side the polarity is reversed. When a train enters a gap, where the polarity isn’t the same at both sides the engine will stall. Then you have to reverse the polarity of the track where your train is heading for. Of course it would be better to set the switches in the right position in advance.
And yes you can buy devices for DCC which change polarity automatically. The gaping remains to be done, just the polarity is switched by the device. A good wiring diagram is added with the purchase.
While it may have been easiest to answer hsi question,
I will play a little [}:)] advocate here.
This site is only ONE SOURCE for information, internet or not. Books, those old fashioned things {or the PDF’s of those books our HOSTS now offer} Are another source.
OFTEN, the information can be had by simply typing in the question {or keyword{S} } to google.
ALso, Our inquisitor MAY NOT have known these two books exist…so our friend who kindly pointed them out, COULD have also instructed him where to shop for such books { The top gray toolbar at the “shop” button, OR the black toolbar at the “Shop” button" } are places to find the WONDERFUL books by our HOSTS here, who HAPPEN TO RUN A MAGAZINE and SELL BOOKS from said magazines!
Both books may provide the inquisitor with a wealth of other info. The books for example have lots of diagrams that can express exactly what to do in “X” situation! . They tend to be “bibles” of the sport we call MRRIng.
Wow, this thread turned contentious very quickly, and no one has really answered the OP’s question.
The circle that I drew on the track diagram indicates the point of reverse polarity. The rails need to be gapped at that point. Then, to fully isloate the reverse loop which has been created, the rails also need to be gapped at two other points as indicated by the X that I placed on the track diagram: at the divergent track to the left of the point of reverse polarity and at the upper left portion of the crossing shown at the bottom center of the track diagram.
An auto-reverser will not function properly on DC, so you need to use DPDT switches as Paul suggests.
now is happening exactly what i meant. People who do not really understand the issue are trying to tell their truth; in the end the original poster will end up asking himself who to believe.
A good book however by a well respected and knowledge-able author is worth its money.
Rich is confused by the wiring needed for a reversing loop. Then both tracks beyond the turnout have to be gaped. The idea is when a train is intending to run counter-clockwise over the reversing loop, you first set the polarity right for the reversing track.(if needed, by accident it could have been OK), by flipping the first DPDT-switch. When the train is completely on the reversing track, you might have to change the polarity of the remainder of the layout. Hence the second DPDT-switch.
On the plan of the original poster you must be able to run the oval without changing polarity. Hence only the part between the oval is used as a reversing track.The procedure is the very same as with a normal reversing loop. Actually there are always two spots where polarity issues exist. At these two spots you have to gap both rails.
One remark, since the whole train has to be on the reversing track, the length of it defines the maximum train-length.
This diagram is a good starting point. Having a “crossover-reverse loop” like this has a problem which is sometimes overlooked in layout planning. The “reversing section” is quite short, and it’s not unusual to have a train’s engine leave the loop at the bottom, say, before the caboose clears the turnout at the top. This can result in a short if the caboose has metal wheels, even more likely if it’s an illuminated passenger train and all the wheels are connected.
With DCC and a fast solid-state autoreverser, I seldom have any problems with my own crossover section. However, DC requires throwing the toggle by hand, and can’t support the millisecond swaps needed to make this work, most of the time.
It may be awkward, but one solution is to include half the outer loop in the reverse section. In the diagram, think of making the whole left-hand side of the outer loop, including the crossover, red. The gaps would move to the right of the turnouts on the outer loop.
To run trains on the outer loop, it’s necessary to make sure the toggles are aligned, but it allows much longer trains to negotiate the loop without shorting.
Disclaimer: The referenced pages are from an electronics vendor who, obviously, are trying to sell product. If you go their suggested route, you might want to shop around for better values (if any exist).
A last drawing about lengthening the reversing track.
The last drawing comes close to what Rich proposed. Anyway now you have to check polarity too when running the oval; though only after you used the reversing track.
BTW where black meets red you will have to gap both rails.
The Original Poster appears to be pretty new to model railroading. A book that he can purchase and have in his hands in a couple of days (from the sources in the links I posted) will have authoritative answers on many questions that will arise in wiring his new layout, such as the locations of gaps and feeders.
He’s already received confused and conflicting answers on this thread. Silly me, I think the OP would be better off with one correct answer than with a half-dozen different answers – some of which are way off the mark for his situation.
I’ve actually helped wire multiple layouts for DC with reversing loops. I have more than a vague idea about what’s needed. (which does not seem to be the case for everyone posting on the thread – but I’m not namin’ names.)
I don’t believe that’s correct. A single toggle won’t work in DC. It typically takes two and a reversing section longer than a train length if you want the train to keep moving – but I’d be interested in your single-toggle-approach for continuous motion reversing with DC if you’d like to draw and post a schematic.
Why not just isolate the diagonal and use one DPDT? If our friend can contain his longest consist between the ends of the turnouts at either end of the diagonal, and if he uses the ends of those turnouts where they diverge as his gapping points, he only needs to reverse that one segment.
I’m not seeing how that’s correct for continuous motion with DC. It seems to me that you’ll need another DPDT to reverse the direction of the rest of the layout when the train emerges from the reversing section, or it will short there. That’s the typical DC technique (and is the basis for the Atlas Controller) – but I’d be interested in learning from your wiring diagram.
If you stop the train every time in the reversing section while you actuate the DPDT and the direction switch on the power pack, then yes, I think a single DPDT will do. But then the “forward” direction on the Power Pack keeps changing every time one transits the reversing section – which is also confusing.
The time-tested DC practice of two DPDTs, one for the reversing section and one for the direction of the main, is usually the best approach for continuous motion in DC, I think. But I’m open to learning of a way to do it with one electrical switch.
(To the Original Poster: this is one of the reasons many folks go to DCC – it’s much easier to automate reversing sections).
Additional issue: If the Original Poster wants more than one train in motion at a time and doesn’t want to stop in the reversing section each time, then he’ll need to add blocks and additional DPDTs for each Power Pack.
Well, I didn’t seem confused before, but now I am. My diagram seems right to me, but if I am wrong, then I am wrong. But, tell me what is wrong with it.
The problem, as I see it, is that everyone else is drawing his own track diagram, not using the OP’s track diagram, and suggesting that this is how to do it.
This is the main layout. Wire it with a DPDT switch as shown. It will work with the switch in either position. Throwing the switch will only reverse the direction the train is traveling.
This is the reversing section. It should be gapped at A and B. Wire it to a second DPDT switch as shown.
This is the layout as the OP posted it. For a train to cross Gap A both switches should be in the same position. For a train to cross Gap B the switches should be in opposite positions.
As drawn, the only way to get the train back on the outer loop traveling in it’s original direction is to back it through the reversing section. There is no way to drive it forward back to the original configuration.
This is a pretty interesting subject! Normally I’m pretty good with old school automotive DC so I understand there can be a couple ways to get something like an alternator to work.
So thanks to the complications of that layout I might actually need three insulating sections. Am I correct in assuming a product like Atlas #55 has plastic joiners and a small section which comes up in the middle at Code 100 rail height to keep the track from connecting as well?
Far as the books go, I probably will order one or two eventually. My automotive Haynes manuals just collect dust on the shelves now as websites like http://www.markviii.org/LOD2/index.htm and www.mustangsandmore.com have given me great step by step instructions on changing from air ride to springs and other things.
As has been mentioned, one toggle for the actual reversing section and another for the rest of the layout, when you exit the reversing section the remainder of the layout that you are now entering will have the wrong polarity and must be reversed in order for the loco to continue. you entered the reversing section in a clockwise rotation and are reentering the main section of the layout in a counterclockwise rotation. the polatity on the main must be reversed. In DCC this is not an issue. in DC it is.
