Re: DCC Bus reversing question


Steve Haas
 

"In the photos area, under my name, as we now can't load JPG files to the files area."

Blair,

I've downloaded and reviewed your JPG.

In my opinion you're making this more complex than it needs to be.

I'll get to that, but first answer a couple of questions:

1) These are the only paths that a train uses to reverse - Yes/No?
2) How much of this trackage has already been built?
3) How much of this trackage that has been built has already been wired?

Back to the track plan:

1) If you remove (for discussion purposes) the double crossover at "Y", all you have are three loops around the layout, never needing to reverse electrical phasing:
A) Loop "C',
B) Loop "C-B-A-B-C", and
C) Loop "C-B-A-D-C".

Wire "Rail A" to the outer rail & "Rail "B" to the inner rail (or vice versa) and you are done with this stage of electrical design - no reversing sections, just straight DCS> Booster>PSX and PSX-AR in parallel (not series) as you have currently noted in the Jpg.

2) Now let's reintroduce that double cross-over - this creates the possibility to reverse trains:

A) Is this track already laid? If not, there's no physical rework needed - just rethinking and re-drawing the wiring specs . . .
B) What is the wiring architecture of the crossover? Are the two paths totally isolated electrically from each other? If they are it eliminates a potentially thorny problem. If not, might need a Tam Valley Frog Juicer to manage the four points in the diamond.
C) Now let's address where to place the reversing sections themselves: Knowing only what you've shared with us and the fact that this a logical and not necessarily a scale drawing of the layout, I'd suggest the following:
i) Two reversing sections:
` a) the first is in the upper right quadrant of loop "A", starting one train length before the upper left turnout in the crossover, and extending to the gaps in all four rails to the right of that turnout,
b) the second is in the lower right quadrant of loop "A", starting one train length before the lower left turnout in the crossover, and extending to the gaps in all four rails to the right of _that_ turnout.
ii) One reversing section:
a) If you are not wedded to the double crossover, and the straight section in the middle of the diagram is physically long enough, consider replacing the double crossover with two single crossovers at least a train length apart. There are folks involved in layout design that suggest this increases operating flexibility - I'm not in a position to comment on that, perhaps others will chime in. If you're interested in this approach, let me know and I can help with location of the single reversing section needed to do things that way.

Note that all variations of what I've suggested eliminates the need to have reversers of any type be in series with PSX units. This is important, because as others have said, A PSX-AR is just another PSX with an AR unit added in - they are not designed to be used in sequence.

Give a holler if you would like to discuss further!

Best regards,

Steve

Steve Haas
Snoqualmie, WA

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