Figure-8 within a loop -- how do I wire it

[Old Jedi]

I am setting up an oval with 4 switches that create a figure 8 in the middle of the oval.  All four switches through:  route is the oval, all four divergent:  route is the figure 8.  This is a DCC layout, and I know I have to isolate the divergent route from all four switches--leaving the cross in the center isolated.  Can I wire this as a single reverse loop with one auto reverser, or do I need to seperate it into two separate reverse loops with a reverser on each one?  I hope this makes sense--I am new to this...  Thanks for your help.

[Nathan]

Do you run more then one train at a time? If yes then you need two reversing sections.

Do any of the cars have lights or use track power for any thing?  If yes, is the train length short enough that the whole train will fit in the length of the reversing section?  If no, then you need to look moving the reversing sections to the main line  dividing it in to two reversing sections and having the figure 8 section as the non-reversing area.

--------  --------
|    \           /    |
|                     |
|       \    /        |
|         \/          |
|         /\          |
|       /   \         |
|                     |
|    /         \      |
--------  --------
The left end with turnouts and half the distance on the outside loop to the next turnout is one reversing section.  The right end is the second reversing section.  The 'X' is the 'normal' section.

[Joe Satnik]

Edit:

Removed obsolete reverser/track gap wiring recipe. 

See new post below.

[Old Jedi]

Thanks for the great instructions guys!  If I understand it right, If everything on a train using power will fit on the track inside the four turnouts (the figure 8 section) then I can use just one reverser and make the entire middle section a reverse loop isolated at the divergent legs of the turnouts.  Also, I assume I cannot use one reverser to control two loops, so each separate loop would require a reverser (as Nathan's plan).  I am using EZ track with the DCC controlled turnouts (haven't placed the order yet)--as it seems to get good reviews.  I just ordered a MRC Prodigy Advance 2 yesterday.  I have the benchwork coming from Sievers (it shipped today)--so I am about to start having fun!!  woopee.  Of course, I am blaming all of this on having grandkids, but we all know the real truth......    Joe, I have a double mainline oval with the inside oval diverging into a figure 8 for reversing purposes.  Both loops are connected via a crossover section of 4 switches.  I wish Bachmann would offer a double crossover #6!  I have an interchange track siding off of the outside oval, and a couple of sidings inside the figure 8 loops.  It is HO scale, 5' x 9'.

[SvFiat]

Old Jedi, I agree with you 100% a #6 double crossover would simplify so many setups especially in rail yards.

Are you listening Mr. Bachmann?

Have Fun

[Joe Satnik]

Dear OJ and All,

I just figured out a nifty DCC single reverser wiring and track gap scheme for the figure 8 within an oval.

No DPDT needed.   

This new scheme is so much better than my previous one that I will remove the old recipe from my post above. 

The only possible drawback is that 2 of the 4 turnouts (if DCC controlled) are powered/controlled off of the output of the reverser.

(Turnouts could be confused or weak from bouncing/reversing DCC signal/power.)

Longest train is a loop (half circle) length plus the shorter of the following:  X (divergent) route length or (straight) through route length.

4 insulated gap pairs:

Northwest turnout - through route

Northeast turnout - divergent route

Southwest turnout - through route

Southeast turnout - divergent route.

DCC Controller output --> east loop and both through routes --> reverser input

Reverser output -->west loop and both X routes
       _
CX  _)

(Weak ascii rendition of the 2 isolated track areas... slide together in your imagination so the underscores are above and below the X.)

Hope this helps.

Sincerely,

Joe Satnik 

Edit: clarifications.

[Old Jedi]

I don't know if this pic will work or not--my first attempt.  If I understand correctly, this wiring should do the trick. I am powering the Auto Reversers from the main buss, but the output only will go to each of the two loops.  All of the light green track will be powered from the main buss.  Does this look right?

[Nathan]

From what I can see on the drawing you have 2 auto-reverse units, one for the Dark section and one for the Light section.  This looks correct for running trains longer then the length of the 'X'.

[Joe Satnik]

Dear OJ,

Wow.  Beautiful diagram.  Which CAD program?  Does it use an EZ-Track library of parts?

If you had a few more inches of board length, you could make the end half circles concentric.  (Beauty in symmetry.)

Note that the figure 8 restricts the length of your trains to the end loop (half circle) + an X section length.  (Loco would crash into its caboose at the 90 degree crossing if longer.)

If you only used the X portion for the turn around loops, (never a figure 8 ) then you could use the 2nd reverser to get the longer train length (= X length + end loop + through route length). 

Otherwise, my single reverser scheme would work for a train length only slightly shorter (= end loop + through route) than the figure 8 restriction (= end loop + X length). 

So, If you wanted to save the money you would spend on the second reverser.....

Hope this helps.

Sincerely,

Joe Satnik

[Old Jedi]

Joe,

I use Anyrail software (anyrail.com) and I really like it.  It does have libraries for nearly all track I have ever heard of, including EZ track.  It isn't free, but I thought the free ones were too hard to use.  This one is easy.  Didn't need to read the manual even.  If I can find plywood and foam subroadbed in a sheet larger than 4 x 8 I may go larger--partly to even up the ends, and partly to give me some more room at the edges.  I didnt want to buy two sheets of 4 x 8 and just use a little of it tho.

What I would really like is to make both loops 22",  but I could't figure out how to make the figure 8 or even just one reversing loop.  I'd love to hear from someone who has.

Sievers' benchwork arrives today, and the Prodigy tomorrow.  Track still waiting for shipment.  At least I can start the fun this evening!

[taz-of-boyds]

Joe,

My brain is not working completely right, I am having a little difficulty picturing your suggestion.  Does it require removing a couple turnouts?

Old Jedi,

If you keep things like they are, I would make one change.  Change the upper center blueish turnout to a pinkish turnout.  That way activity on the pinkish loop to the outer loop would not interfere with activity on the blueish loop and inner X tracks.

Have fun,
Charles

[bevernie]

 :DGREETINGS!! ???Will this layout work for a DC set-up?
                                                                                               THANX!!
                                                                                               Ernie

[Joe Satnik]

Taz,

Yes, it is simplified in that it only shows the inside combination oval/figure 8 that uses 4 turnouts (no outer oval). 

Remove the straight through routes (underscores on my ascii diagram)  and replace them with 4 turnouts in a crossover configuration to the added outside oval.

The outside oval, the crossover turnouts, and the inside east loop (half circle) are all (DCC only) Main Bus power.   

The inside west loop (half circle) and both legs of the X are all (DCC only) Reverser Output power. 

The placement of the four pairs of gaps (or insulated rail connectors) is critical.  Through route = straight route.   Insulating connectors should be right off the turnouts, or gaps as close as possible to the turnouts on the attached track. 

4 insulated gap pairs:

Northwest turnout - through route

Northeast turnout - divergent route

Southwest turnout - through route

Southeast turnout - divergent route.

Hope this helps.

Sincerely,

Joe Satnik

Ernie,

Yes, with restrictions and a DPDT switch.  Details later.

[Joe Satnik]

Make that 2 DPDT switches and an 1156 tail light bulb for the DC-Block version. 

                  mmmmmmmmmmmmmmmmmm
             mm                 m                             mm
        mm                          m                              mm
      m    rrrrrrrrGmmmmmmmmmmmmmmmm         m
    m    rr        r                                 G            m       m
  m   r                  r                          r                  m     m
m    r                       r                 r                         m    m
m  r                               r       r                             m    m
m  r                                   r                                 m    m
m  r                               r       r                             m    m
m   r                        r                  r                      m     m
  m   r                  r                           r                m    m
    m   rr         r                                  G          m      m
      m    rrrrrrrrGmmmmmmmmmmmmmmmm       m
        mm                         m                               mm
             mm                 m                              mm
                  mmmmmmmmmmmmmmmmmmm

Not sure why the ascii diagram shows up as it does with the gaps on the right side.

m = wired as "main" tracks.
r = wired as "reversing" tracks. 
G = gap pair or insulated rail connector pair.

4 gap pairs or insulated rail connector pairs:

Northwest turnout - through route

Northeast turnout - divergent route

Southwest turnout - through route

Southeast turnout - divergent route.


Main DPDT and Reverse DPDT switches:

1 2 3
4 5 6

Power pack (+)DC -->1156 tail lamp tip

1156 tail lamp outer case --> Main DPDT 1 and 6 -->Reverse DPDT 1 and 6

Power pack (-)DC --> Main DPDT 3 and 4 --> Reverse DPDT 3 and 4

main DPDT 2 --> Main tracks outer rail

main DPDT 5 --> Main tracks inner rail

reverse DPDT 2 --> Reverse tracks outer rail

reverse DPDT 5 --> Reverse tracks inner rail

Label the DPDT switches CCW (counter clock wise) in the paddle direction that connects 1-2 and 4-5

Label the DPDT switches CW (clock wise) in the paddle direction that connects 2-3 and 5-6

Hope this helps. 

Sincerely,

Joe Satnik

[taz-of-boyds]

Old Jedi,

I see it looks like you updated your diagram, looks good.

Joe,

Thanks for the clarification, you have a lot of patience with character graphics.  Maybe you could move the gaps on the right hand side of the loop in to be adjacent to the crossing?  This would even out the available length for trains being the half circle and half the crossing length for either side of the loops.

Great stuff,
Charles