Guy PapillonSo my questions are : Can I keep the wiring as it is (allowing current on only one track at a time)? Do I need one or two PSX-AR? If only one PSX-AR, should I place it between switch A and the gap?
You can not keep the wiring as it is. The PSX-AR has it's own requirement.
You only need one.
It is not placed "between" anything.
You will need both rails of both tracks gapped just past switch A before the other two switches. Your DCC bus will feed the main, and the PSX-AR will attach to the bus and feed the loop. Whenever a gap is spanned (creating a short), the PSX-AR will detect the short and switch the polarity of the loop to match. It will also throw the Tortoise to line up in the direction the train is comming from. You don't care which way the switch is thrown when you are entering the loop.
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Hi,
I understand that my question lacked precision. Here is the exact sitation:
Actually the Turtoise that controls Switch A determine the polarity of the loop. Turtoise that controls Switch B will allow the current on one track or the other (remmant of the DC wiring).
So my questions are :
Can I keep the wiring as it is (allowing current on only one track at a time)?
Do I need one or two PSX-AR?
If only one PSX-AR, should I place it between switch A and the gap?
Thank you.
Guy
Modeling CNR in the 50's
While not directly relevant to the OP's question, it points out how sometimes you want to change the square hole to a round one if you only have a round stick to put into it In other words, careful design often used for DC control offers a few advantages if this will be a DCC powered layout while limiting the possibility of conflicts described above already. Some thought needs to be given to how the OP intends to use the loop.
In a case like this, I recommend using track design to limit the possibility of having two sets of gaps crossed at the same. Here it's example A. While two trains might be moving within the reverse loop behind the gaps, it's physically impossible to cross two sets of gaps because there's only one set.
That's how my Chama staging loop is set up. The loop is big enough so it's seperated into 4 blocks, with each loop track being gapped internally to the loop. This is because I built for DC control originally.
Depending on the available visibility and other goals for such an arrangement, making it one way helps further limit the possibility of conflicts. In my case, the loop is hidden under the main part of the layout and monitored by CCTV. There I made the exiting turnout from the siding that brings the two tracks back together power routing to feed the two blocks that lead to it. That way motive power can't advance to the second block in each track unless that turnout the merges them back together is set to allow the train to pass. Alternatively, you can run trains into those tracks when they are dead and use that for a safe, no-spark "capture zone" that's very helpful if this was DC and still useful with DCC.
I am the only one who operates the Chama loop, so all the power switches are conventional "throw and stay" type. If it was going to be operated by multiple people with less experience and habit than myself, then making the power switches spring-loaded so they must be held in place until movement they control is complete could be another useful design feature borrowed from DC if this will be DCC power.
Mike Lehman
Urbana, IL
carl425 richhotrain one PSX-AR should be sufficient since it is unlikely that one train will still be entering the loop as another train is exiting the loop. If it is unlikely to have a train on both tracks of the double track loop, why would it be double track? The fact that it is double track implies that it is indeed likely. If it is possible to have trains on both tracks at the same time I think you should use 2 PSX-AR's.
richhotrain one PSX-AR should be sufficient since it is unlikely that one train will still be entering the loop as another train is exiting the loop.
If it is unlikely to have a train on both tracks of the double track loop, why would it be double track? The fact that it is double track implies that it is indeed likely. If it is possible to have trains on both tracks at the same time I think you should use 2 PSX-AR's.
If, instead, it is B, then where are the crossovers placed to make one or the other track a siding?
Rich
Alton Junction
carl425 gmpullman Rich is making a point that without any kind of track plan to look at we are just speculating here. Good point. Is it like A or B? A needs only one AR, B needs 2.
gmpullman Rich is making a point that without any kind of track plan to look at we are just speculating here.
Good point.
Is it like A or B? A needs only one AR, B needs 2.
That was the basis for my initial reply.
gmpullmanRich is making a point that without any kind of track plan to look at we are just speculating here.
carl425 gmpullman OR cars with electrical pickups You don't need electrical pickups to trip the AR. All you need is a metal wheel.
gmpullman OR cars with electrical pickups
You don't need electrical pickups to trip the AR. All you need is a metal wheel.
I'm just sayin' if you run passenger trains they will bridge the gap (85 feet worth!) and they will short IF they happen to be bridging the exit gap at the same time a train may be crossing the entrance gap.
I agree with you that if this is truly double track then two ARs are called for.
Rich is making a point that without any kind of track plan to look at we are just speculating here.
#1 rule in using any auto reverser. Only one set of gaps can be crossed at a time.
Thanks, Ed
gmpullmanOR cars with electrical pickups
richhotrainone PSX-AR should be sufficient since it is unlikely that one train will still be entering the loop as another train is exiting the loop.
One reverser will get you by IF there would never be a chance of one set of gaps being crossed by locomotives OR cars with electrical pickups at the same time any of the three other sets of gaps were being crossed.
If your second track is strictly a siding you may not have to be concerned but if there were ever a chance of trains moving on both tracks simultaneously, sooner or later you will probably create a short that the auto reverser can not compensate for. In that case you would need an auto reverser for each track of the double track loop.
Passenger cars with lighting pickups crossing the gap will cause it to short as well if more than one gap were bridged so you have to keep that in mind, too.
Hope this helps, Ed
Depending upon the exact track design and the placement of your gaps, one PSX-AR should be sufficient since it is unlikely that one train will still be entering the loop as another train is exiting the loop.
Just place your gaps inside and as close to the beginning of the loop as possible. Same for the turnouts which begin the siding inside the loop.
I want to install a PSX-AR in a double track reverse loop. When using the loop, either track can be used as a siding. Do I need to install two PSX-AR or one will work?