Electrofrog points DCC Layout where to fit insulated rail joiners

[annette]

Help! Can someone tell me where to add insulated rail joiners on my DCC layout with electrofrog points please?

Thank you! Annette

[Grovenor]

The answer has already been provided in the duplicate topic in the DCC section!

Both the wrong answer as here, and the correct answer of I/Js on the two rails coming off the frog of each point, so 4 I/Js per crossover, 8 in total for the layout.

[annette]

Thank you Keith, that's kind of you to reply! I now have done what you suggest and it all is working beautifully now! Best wishes, Annette 

[annette]

Me again! Sorry, to re-post for more advice! I have now added an inner loop (which I have called 'right larger loop') and it runs beautifully. So I also bravely attempted to add another inner loop (which I have called 'left smaller loop') which does not work, and shorts. This is the section between the points marked A to B. Would any of you lovely experts suggest where I need to add insulated rail joiners and power feeds please? I have indicated where I have already placed IRJs and power feeds to the track. Electrofrog points throughout and DCC. I promise not to trouble you a 3rd time! Thanks (in advance!).  Annette 

 

Double loops.docx

[Michael Hodgson]

You've added a reverse loop (the bit shown in grey).

That means the outer rail is connected to the inner rail.

That would be a problem on a DC layout too.

You should install an auto-reverser module (various makes on the market - I would expect it to come with instructions).

[Dungrange]

As above, you have created a reverse loop. 

 

On a DC layout, this would be handled by completely isolating your grey track using four insulated joiners: one on each rail at each end of the section (ie close to points A and B).  What is important is that the length of the isolated section is longer than the longest train you plan to run.  This section would then be fed through a Double Pole Double Throw (DPDT) switch, so that it is connected to the track at the side you are approaching from.  Once the train is in the section, you'd stop the train, throw the switch such that it is then connected to the exit track and drive the train out, noting that you'd have to change the direction switch to keep driving in the same direction, because the polarity of the rails has been switched.

 

On a DCC layout, you'd effectively be taking the same approach, fully isolate the section of track between points A and B and then you feed this through an auto-reverse module.  Effectively this detects a momentary short on entry and automatically switches the connections over and does exactly the same when it detects a momentary short on exit.  Unfortunately I've no experience of using auto reverse modules, so I can't advise on which is best or most reliable.

[annette]

Thanks you Michael and David for your time in looking at the problem! I tried all variations of isolated rail joiners and track feeds, but all defeated me! I understand why now, and how to solve it. However, I don't think I'll attempt an auto reverse module - am at a basic digital model railway stage of learning!  Best wishes. Annette 

[Chimer]

Nothing to do with the electrickery, but are you happy that with this layout, using the reverse loop will mean all your trains will end up running clockwise, whichever circuit they are on?  Not such a problem* if they're all multiple units which can just reverse, but something to think about with "real" locos, especially steamers ......

 

* except that in normal British double-track practice, traffic should be clockwise on the outer circuit and anti-clockwise on the inner.

 

Anyway, just for fun I did this, which feels in the spirit of your design but addresses those two issues.  No idea whether you've got the space .... it uses 4th radius curves on the inner circuit, 4th + 2" on the outer, and 2nd radius curves on the return loops (which would both need fixing electrically as others have advised).  1 ft squares, so 8' x 6'6", roughly.

 

 

A train running correctly clockwise on the outer circuit would take the first crossover and the following point into the right hand loop, emerging on the far right running anti-clockwise on the inner circuit.  To return, it takes the point on the far left into the left hand loop and then the other crossover back onto the outer circuit.  So everything can go everywhere, running in the right direction at almost all times.

[Harlequin]

On 02/02/2022 at 21:59, annette said:

Thanks you Michael and David for your time in looking at the problem! I tried all variations of isolated rail joiners and track feeds, but all defeated me! I understand why now, and how to solve it. However, I don't think I'll attempt an auto reverse module - am at a basic digital model railway stage of learning!  Best wishes. Annette 

 

Don't fear the auto reverser. Two wires in, two wires out (to the track) fit and forget.

 

[melmerby]

13 minutes ago, Harlequin said:

 

Don't fear the auto reverser. Two wires in, two wires out (to the track) fit and forget.

 

Depends on the type

 

Frog Juicer.

Proper auto-reverser using short circuit detection.

Proper auto-reverser not using short circuit detection.

 

N.B. I have two of the last type, they are the more complicated of the three to wire but there is never a short across the track.

(don't ask me how they work - I don't know, they just work!)