Reverse Loop problem

[ronpixe]

Can anyone help in suggesting were I should install the the reverse loop wiring in the attached layout.

I have tried a number of options but I am not getting it right.

The layout is DCC and I will be using a Digitrax AR1 to manage the loop.

4x2 new layout.pdf

[5BarVT]

I don’t have a reverse loop so can’t say ‘been there, done that’, but I would connect all of the loop to the AR1.  That is, double insulated rails at the end of the reverse loop point on each leg.  That way, only one train can be across the ‘station’/loop join at any one time.

(Or if there are two trains, you’ve got bigger problems than loop polarity!!!)

HTH

Paul.

[The Stationmaster]

1 hour ago, 5BarVT said:

I don’t have a reverse loop so can’t say ‘been there, done that’, but I would connect all of the loop to the AR1.  That is, double insulated rails at the end of the reverse loop point on each leg.  That way, only one train can be across the ‘station’/loop join at any one time.

(Or if there are two trains, you’ve got bigger problems than loop polarity!!!)

HTH

Paul.

But you can create separate sections within it although double insulated rails would again be needed between any section(s) which hold arriving trains and any which hold departing train(s).

 

On a previous layout many years ago the 'return loop' consisted of four parallel loops and each loop was divided into two sections.  That meant a double insulated rail joint between the two sections on each loop and another double insulated joint at the departure end of each loop.  The second section of each loop used a changeover switch allowing it to be used for either arrival/moving up or departure while the first section was always connected to the arrival section.

[ITG]

I use the Gaugemaster reverse loop module, and as stated above, the entire loop must be isolated completely in both rails at both ends.  I then feed into the module with a normal track feed (as with any other dropper) and out to what in my case is several feeds into the reverse loop.

[ronpixe]

Having spent the morning working on it now managed to work it out and everything running fine.

[RobinofLoxley]

Pleased to hear you got it working as im not sure anyone provided you with what you needed. As Paul said, what is critical is that only one current drawing item (so not just a loco but a lit coach would draw current, etc etc) crosses the boundary you set between track sections that dont need to change polarity and those that do. In your case, you could place that boundary anywhere within reason within the loop section, but it would be better to keep one end at the curved part of the point, and the switched section would then be set up longer than the longest train you might ever run, but doesnt have to be the full length of the loop itself.

[5BarVT]

2 hours ago, RobinofLoxley said:

Pleased to hear you got it working as im not sure anyone provided you with what you needed. As Paul said, what is critical is that only one current drawing item (so not just a loco but a lit coach would draw current, etc etc) crosses the boundary you set between track sections that dont need to change polarity and those that do. In your case, you could place that boundary anywhere within reason within the loop section, but it would be better to keep one end at the curved part of the point, and the switched section would then be set up longer than the longest train you might ever run, but doesnt have to be the full length of the loop itself.

Agreed, it doesn’t have to be the full length of the loop and as long as it’s longer than any train then running one train through won’t cause a problem.  But (!), it’s DCC, so there could be two trains one following the other, which could foul things up.

The ‘clever’ bit of my suggestion was to make the whole of the loop the reversing section so that physical constraints prevent two trains crossing the boundaries at the same time.

Paul.

P.S. Glad it’s working now.

[St Enodoc]

11 hours ago, The Stationmaster said:

But you can create separate sections within it although double insulated rails would again be needed between any section(s) which hold arriving trains and any which hold departing train(s).

 

On a previous layout many years ago the 'return loop' consisted of four parallel loops and each loop was divided into two sections.  That meant a double insulated rail joint between the two sections on each loop and another double insulated joint at the departure end of each loop.  The second section of each loop used a changeover switch allowing it to be used for either arrival/moving up or departure while the first section was always connected to the arrival section.

No need Mike! Don't forget DCC is only two wires (yeah, right...).

[St Enodoc]

8 hours ago, ronpixe said:

Having spent the morning working on it now managed to work it out and everything running fine.

Make sure you have good access to the point in the tunnel. It's a law of nature that it will be the only one that ever goes wrong.

[The Stationmaster]

13 hours ago, St Enodoc said:

No need Mike! Don't forget DCC is only two wires (yeah, right...).

When I last wired a return loop the early US 'command control' equivalents of DCC (much less sophisticated of course) had hardly been heard of on our side of the pond

[Confused.com]

I have a different problem but seems to fit in here.

I have a "Y" junction leading to a station from 2 points on the main track.

I have installed a Gaugemaster auto reverse module. 

The track is powered by a Bachmann Dynamis Ultima system.

I have isolated both ends of the Y and installed the unit near one end red wires to the main track side yellow wires to the Y.

I can get locomotives to enter/exit the Y from the side away from the Gaugemaster unit  but when they try to enter/exit from the unit end I get a short circuit.

Any suggestions please.

Thanks

 

[Grovenor]

Can you provide a diagram showing your connections, and what kind of points, electrofrog/insulfrog etc. and locations of insulating joiners?

[Confused.com]

Will do tomorrow. 

[Confused.com]

Here is a sketch of the track plan . Hope you can help. Thanks

Y track plan.pdf

[ITG]

I would have thought that when you have the route set to travel east>south (or vice versa) that you need additional rail breaks on that connecting leg. Otherwise the (east) insulfrog point is routing current down towards your DCC80 yellow wires, which have reversed the polarity of the current coming from the south - hence the + meets the - and vice versa. 

[Confused.com]

Thanks for that I will see if that solves the problem

[5BarVT]

Continuing along the ITG theme: does the line at East connect to anywhere else on the layout?

If yes, then you will need another set of insulated joints in that connection.

If no, then are there any other track feeds to the right of the sets of insulated joints? (For the ARM to work properly all of the track in the section it controls must be fed through it with nothing in that whole section fed direct from the controller.)

Your description of the fault suggests to me that the ARM isn’t switching; so it happens to work for the direction where the polarity is the same and doesn’t when the polarity needs to be reversed.

Paul.

[DCB]

I think you are trying to reverse the polarity of the whole station instead of a short connecting link.  SEE PIC

The train needs to start from the station reverse polarity to go South compared to North with your set up.  
That said short link should ideally be longer than your longest train if you have metal wheels/ pickups on the rolling stock or you will get a repetitive shorts as trains longer than the isolated section short out both your sets of isolators simultaneously.  

 

Edited August 6, 2022 by DCB

[Grovenor]

There should be no problem reversing the polarity of the whole station and the wiring should work as is provided there are no other feeds on the East leg.  If there are indeed no other feeds then it suggests that the DCC40 is not working. An alternative is to use an isolated side of the triangle as shown by DCB but you could get problems with trains longer than the isolated section. Trying it, however, with a short train would allow you to find out if the DCC40 is working or not.

Edited August 8, 2022 by Grovenor

[Confused.com]

Thanks for all your suggestions. I have found out that the problem was being caused by the point clips I had installed on the points. Took them off and the DCC40 works fine.

Thanks again

PS I have removed the double set of points to simplify the layout.

Edited August 8, 2022 by Confused.com
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