Reverse Loop in Atlas #27 Transbay

[Anonymous]

Hello All,

 

I am new to the hobby and could use some guidance.

 I am running the Atlas #27 Transbay Interwoven track layout on an all DCC system.  I followed the directions as layed out in the Atlas book I used - installing only the double-blocks as directed by my LHS.  I have the track installed, however I am routinely receiving the SVDA - short code on my Prodigy Express unit.  I believe I need to run two AR1 units in this double reversing setup...but am unfamiliar with the concepts of electricity and wiring.  Basically, I know how to turn on the light switch and viola, the light comes on...

Please advise as to how this design should be wired, including the AR1 lead placement.  As I am new to the hobby, please be sensitive to making any assumptions of knowledge or understanding of the hobby vernacular.

Thank you and I look forward to the insight offered by the forum.

 

[Texas Zepher]

I am running the Atlas #27 Transbay Interwoven track layout on an all DCC system.  I followed the directions as layed out in the Atlas book I used - installing only the double-blocks as directed by my LHS.

And what double-blocks are those?  Are they different than the ones specified in the Atlas book?

I believe I need to run two AR1 units

What is an AR1 unit?  Some specific vendors model number for an automatic reversing circuit?

Please advise as to how this design should be wired, including the AR1 lead placement.

I thought the book was pretty clear.  Assuming the double gaps are done like the book, then one auto reversing circuit should be connected to the straight X and y terminals, the other to the X prime and Y prime terminals.   The straight DCC output goes to the pairs of 2, 2C; 3, 3C; 4, 4C; 5, 5C; 6, 6C; 7, 7C; and 8, 8C.  Of course for DCC terminal sets 5, 6, 7 & 8 are basically the same thing.  The 6 and 6C on the turntable IS still required for DCC.   The programming track output goes to 1 & 1C.

In general it is best to think of this layout as a figure-8 with two cut offs. 

[Anonymous]

TX Zephir,

 Thank you for your response as well as your patience as we move forward.

I am running the double blocks as listed in the book (the LHS suggested that I did not need the single blocks as those were for DC).  Thus I followed the book as instructed (on the double blocks).

An AR1 Unit is an Auto Reversing Unit from Digitrax.

As for the wiring.  Each AR1 has 5 terminals.  I am directed to "Connect Track Power from Rail A and Rail B mainline to terminals 4 and 5 on the AR1 and then connect the wires from the reversing section to terminals 1 and 2 on the AR1."

Does this mean that I use two connectors, X and Y as well as X' and Y', placing X and Y into terminals 4 and 5, then placing X' and Y' into 1 and 2?

Also, do I place a second AR1 unit in a different area and do the same thing?

Please advise. Thank you.

 

[Texas Zepher]

I am running the double blocks as listed in the book (the LHS suggested that I did not need the single blocks as those were for DC).  Thus I followed the book as instructed (on the double blocks).

Excellent, Yes they were correct the single blocks are not needed.

As for the wiring.  Each AR1 has 5 terminals.  I am directed to "Connect Track Power from Rail A and Rail B mainline to terminals 4 and 5 on the AR1 and then connect the wires from the reversing section to terminals 1 and 2 on the AR1."

Does this mean that I use two connectors, X and Y as well as X' and Y', placing X and Y into terminals 4 and 5, then placing X' and Y' into 1 and 2?

Ummm No.  That would be connecting the two reversing loops together ...

The power output from the DCC system goes to where the AR1 wiring diagram says "Track A & Track B".  Those are AR1 terminals 4 and 5.  This can come off the track or directly from the DCC unit - doesn't matter. Then looking at the Atlas track diagram find the large "Y" near the lower left side.  Just to the right of that is a track marked T (terminal track) with arrows pointing to it labled X & Y.  Connect the Digitrax AR1 terminals 1 and 2 to that X & Y.   [Digitrax terminals in red, Atlas terminals in blue]

Then the second AR1 would likewise have terminals 4 and 5 go directly to the DCC power output or track, but its terminals 1 & 2 would go to the Atlas track plan terminal track that is directly below the large Y' (y prime just a bit further to the right and up from the ones above. One track off the turn table is sort of pointing to it).  The blue arrows are marked X' and Y'.  Connect the second AR1 terminals 1 and 2 here.

Well some of that is sort of redundant but hopefully it conveys the message.  By the way I am assuming you have this track plan diagram from the Atlas book "Seven Step by Step HO Railroads" page 28.  That is the diagram I am quoting the numbers off of. If not let me know and I'll try a different description.

Also http://www.digitrax.com/ftp/ar1.pdf 

[Duker]

Hi I am very new to Model railroading and i'm sure i will have a lot of questions going forward, so joing this site may help me. So my very first search landed on your comments about AR1's and the # 27 Transbay layout, my question was the very same and your explaination was excellent , so thank you for this.

[richhotrain]

Geez, I have five separate reversing sections on my layout, and each is controlled by a separate AR-1.  I love to tackle reverse polarity track configurations, but this thread so far would test anyone's comprehension.  A track diagram would help.

Here is a link to another guy struggling with the wiring issues on that layout.  It includes a track diagram and a colored coded solution to the two reverse polarity situations.

http://www.trainboard.com/grapevine/showthread.php?94913-Transbay-Reverse-Loop-Wiring

Rich