I just moved and am starting a new layout. Since I am starting over, I have decided to go the DCC route. My new layout will have 2 reverse, or return, loops and depending on which article I read, I can either use 2 DPDT switches per loop or use an automatic reverser. One option is significantly more expensive than the other, and is it worth the extra money? I have not purchased the DCC system yet but am considering both the Prodigy Advance and the Digitrax Super Chief at the moment. Does a tethered control have an effect on which way I wire the reverse loops? Any help would be appreciated. Thanks.
I just installed my first ever auto-reverser. My NCE Powercab system is supposed to be a bit tempermental with some reversers so I installed a DCC Specialties PSX-AR. It was very easy to hook up and works perfectly- I don't even have to think about the reverse loop polarity. Tethered control is no problem and doesn't affect hookup. Whether it is worth the cost or not is up to you, but I have no regrets.
Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger... doing it my way. Now working on phase 3. - Walt
For photos and more: http://www.wkhobbies.com/model-railroad/
I also have the PSX-AR's. I'm using mine with Digitrax. They work perfectly.
One thing Walt left out is that the PSX-AR will also control the turnout for the loop - making your loop-to-loop operation completely automatic.
On your DCC system choice, I have no view of the market other than what I read on the forums and the few folks I talk to, but it seems to me that NCE and Digitrax have about 99% of the market between them and the other handful of vendors split the remainder.
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
I also have the PSX-ARs on my two reverse loops. I started with a reverser that only changed the polarity. The PSX-ARs change polarity and throw the switch. I also added manual push buttons on one PSX-AR so I could manually throw the switch.
The PSX-ARs also have an adjustable circut breaker built in.
I have two reversers, OG-ARs from Tonys Trains. Delighted with them. I have all my turnout controls on a scematic control panel with DPDTs and LED indication.
Paul
Modeling HO with a transition era UP bent
I have four reversing sections on my layout, each powered and controlled by a PSX-AR. They work beautifully.
The DPDT switch is incredibly cheaper than a PSX-AR and works just as well, just not automatically. So, if you are prepared to flip the DPDT toggle switch at the correct moment in time, the DPDT is the answer. My preference? The more expensive auto-reverser.
Rich
Alton Junction
richhotrain I have four reversing sections on my layout, each powered and controlled by a PSX-AR. They work beautifully. The DPDT switch is incredibly cheaper than a PSX-AR and works just as well, just not automatically. So, if you are prepared to flip the DPDT toggle switch at the correct moment in time, the DPDT is the answer. My preference? The more expensive auto-reverser. Rich
I am leaning toward using the DPDT option, at least temporarily, for financial reasons. The DCC system itself will take a good hunk of my nest egg. You mentioned 'the correct moment in time'. I was under the impression that as long as the entire train is within the loop, it is OK to throw the switch. Is this correct? And once the train leaves the loop, do I have to throw the switch back to the original position? I had intended on labeling the switch clockwise/counterclockwise, or is that necessary?
I appreciate your advice.
Pappy
If you go with auto-reversers you will thank yourself later. I am using the Digitrax AR-1's with my NCE PowerPro system and they work flawlessly.
Mike
Pappy, what I meant by "the correct moment in time" was to flip the switch before the short occurs. With an auto-reverser, the short is instantly detected and the polarities are matched. It happens so fast that the train's movement is unaffected.
With a DPDT switch, you need to manually throw it in time to prevent the short from occurring. Once you flip the DPDT switch, the polarities are matched, so you do not immediately have to throw the DPDT switch back to its original position. But, eventually mismatched polarities will be encountered once again by the moving train, so you need to be ready to flip the DPDT switch again.
When I used to use DPDT switches for this purpose, I set up LED's so that I could visually determine when reverse polarity was about to be encountered by a moving train.
richhotrain Pappy, what I meant by "the correct moment in time" was to flip the switch before the short occurs. With an auto-reverser, the short is instantly detected and the polarities are matched. It happens so fast that the train's movement is unaffected. With a DPDT switch, you need to manually throw it in time to prevent the short from occurring. Once you flip the DPDT switch, the polarities are matched, so you do not immediately have to throw the DPDT switch back to its original position. But, eventually mismatched polarities will be encountered once again by the moving train, so you need to be ready to flip the DPDT switch again. When I used to use DPDT switches for this purpose, I set up LED's so that I could visually determine when reverse polarity was about to be encountered by a moving train. Rich
Thank you for the explanation, although I am not too savvy on electrical stuff. I think I just might find a way to scrape up enough to purchase a couple of auto-reversers, along with the DCC system.
[Edited by admin to move new text outside quote box. Pappy, when quoting someone else in a reply, start your reply below the "/quote" tag, or else your reply will show up inside the quote box, and readers will think there's nothing new in your post to read.]
carl425I would link the switch to the turnout that makes the loop.
would it control the polarity in the reverse loop or mainline?
greg - Philadelphia & Reading / Reading
If it controlled the main you could use it for DC or DCC. For DCC you can just flip the loop under the train.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
rrinkerFor DCC you can just flip the loop under the train.
i understand that. But there would be a momentary loss of power to the train in the reverse section. But this would probably be preferred if there were other trains on the mainline.
So there's an option
If you use a relay trigged by the switch machine contacts, it would be no more interruption than from a automatic revese unit. You might be able to catch a headlight flicker, but there should be no sound interruptions, even on locos without external keep alives. If the switching element is a toggle or slide switch uses as the "switch machine" - Blue Point, Bullfrog, various DIY methods that have been published - it probbaly is still ok if you just open or close the points rather than slowly slide the operating knob in or out.For a wye arrangement, at least if it's a turning wye, you'd have the loco stopped on the tail track when throwing the switch anyway.
gregc carl425 I would link the switch to the turnout that makes the loop. would it control the polarity in the reverse loop or mainline?
carl425 I would link the switch to the turnout that makes the loop.
I would use it to control the reverse loop. Since he has two loops, it would take some fancy wiring to allow the turnouts for each loop to reverse the mainline.
I use a turntable to reverse engines and the Digitrax AR-1 works fine after a bit of adjustment of the trip point potentiometer on the board. It is worth fiddling with this a bit. Once the right spot on the pot is found, I don't even sense the reversal as the loco's pilot truck comes of the table.
Richard
If I can't fix it, I can fix it so it can't be fixed
So I have always been interested in how exactly a reverse loop with a DPDT switch works exactly. My perception is as follows - an engine enters the loop with the polarity of the reverse loop matching the polarity of the main. Then after entering the loop you stop the engine, throw switch to change the polarity to match the exit rails of the main, and reverse the direct switch on the throttle. Then proceed. Is this correct?
that's one approach
another common approach is to reverse the polarity of the mainline after the engine enters the reverse loop. This avoids changing the polarity of both the reverse loop and the cab.
Tophias So I have always been interested in how exactly a reverse loop with a DPDT switch works exactly. My perception is as follows - an engine enters the loop with the polarity of the reverse loop matching the polarity of the main. Then after entering the loop you stop the engine, throw switch to change the polarity to match the exit rails of the main, and reverse the direct switch on the throttle. Then proceed. Is this correct?
http://www.azatrax.com/model-railroad-reverse-loop.html