wiring question (reverse loop)

[budinoh]

I am working on the design for my new layout and have a wiring question. My plan calls for a 16x16 foot l-shape layout. it will be a folded dogbone design. One end will have 2 return ovals stacked with an upper and lower level. It will appear that I have a double mainline on both the upper and lower levels. As long as I isolate both tracks and do not run common rail wiring, can I put crossovers in the 2 lines without causing a reverse loop as long as the train switches back over to the track it was running on? I want to use the double appearence but use them as passing sidings as well.

I was told that a reverse loop is only caused if you have common rail wiring. Is that true?

Thanks,
Jeff

 

[LoudMusic]

If this is what you're talking about doing then you will need to wire for reversing loops. Otherwise, a drawing would help explain your intentions

 

[CBCNSfan]

I don't think it's a current limiter per-se - They detect a short circuit and switch the phase of the DCC signal faster than the booster can shut down.

Pretty good reading here: http://www.tonystrains.com/technews/powershield_icb.htm

Note the adjustments you can make - Some of 'em got *horrible* reviews as they'd shut down and/or flip with "no warning" - Drove people nuts!

Cheers,
Ian
PS - Tom, given your expressed love of things electronic, you gotta go DCC IMHO

I copied this post by fast_ian from another thread and the link should give you the information you need

Cheers
Willis

 

[budinoh]

In a nutshell yes. Just bend it in half. Now my question would be with both rails isolated, would I still have problems if I took a train headed east on the outside rail and switched it to the inside rail on the crossover to the right, pass around a train headed west on the same outside track, would I still have a reverse problem if I switched the eastbound train back to the outside rail before the loop.

 

[lmackattack]

it will not be an issue if you use an auto reverser. the reverser unit will do all the power switching for you. what you will need to do is isolate about 2' of mainline of each loop. the reverser will just switch power back and forth for that section as it sees needed. the rest of the layout will operate as normal and just those 2' sections will alternate the DCC signal.

hope that makes sence

Trent

 

[TomR]

Using the posted drawing...

If you look at the drawing above and mark the outer rail + and inner -, you will see the cross overs connect the + to the - rails if they are directly connected. That means a short.

When I do this stuff, I mark the each of the two rails in a track in a drawing like above with + and - (or 1 and 2 or dot or square or any two things) and see what happens, if at any point in the system + and - interchange. That helps keep me from making shorts.

If they do, you have a short. The short would be there common rail or not. Both rails would just need to be insulated at the reverser section (or the source for that section independent of other sources), so the rest of the layout could be common rail.

Tom

 

[budinoh]

Ok, I think I am a little lost with what I actually have. So rather than change me layout design, where would my reverse section be and how would I wire it? Do I need oneof those Atlas connectors? I am running DC so I don't believe the auto things would work for me. And I am guessing I would have 2, one at both ends?

 

[Rico]

What you actually have is two reverse loops.
Take away the lower track in blue and you'll see it.
You would have to isolate both rails where the red lines are and use two reversers or two bridge rectifiers.
There's another post with links and descriptions for that.
Clear as mud?

 

[budinoh]

Ok, here is a very rough drawing of my layout design. Sorry for the crudeness. The breakdown is as follows. Folded dogbone, black line is track line, yellow lines are crossovers. I want the appearence of a double track mainline and use the crossovers to create passing sidings. Numbers represent blocks. Blocks are controled by DPDT toggles. Question is how many reverse loop sections do I have? I showed it to several guys at a train show today and the number ranged from 0 to one at each crossover. I am thinking 2. Just at the end loops. Can anyone give me an accurate idea? I may have to change my whole layout design if I have more than 2.

Thanks,
Bud

 

[TomR]

Ok, here is a very rough drawing of my layout design. Sorry for the crudeness. The breakdown is as follows. Folded dogbone, black line is track line, yellow lines are crossovers. I want the appearence of a double track mainline and use the crossovers to create passing sidings. Numbers represent blocks. Blocks are controled by DPDT toggles. Question is how many reverse loop sections do I have? I showed it to several guys at a train show today and the number ranged from 0 to one at each crossover. I am thinking 2. Just at the end loops. Can anyone give me an accurate idea? I may have to change my whole layout design if I have more than 2.

Thanks,
Bud

Assuming both parallel main lines have the same polarity the only two problem points I see are 8 and 22. Both 8 and 22 could cross connect the rails. Of course any crossover could be a potential problem, if the two parallel lines have opposite polarity.

I'm not sure how you are going to wire all that.

 

[lmackattack]

If im looking at that correctly you have a reversloop at just about every switch. you would have to isolate at the crossovers with a length of about a 1' section of track on either side of the switch. this way when a train is going to cross over. the train will enter the isolated section move they the crossover and then exit the isolated section. you will need to draw this out in large scale, color code each rail, then follow your rails to see where they will cause issue. I see alot of auto reversers needed in your track plan.

 

[budinoh]

Allow me to add that this is DC and not common rail. Do I need to start over and redesign this?

 

[lmackattack]

I would say if you were in DCC it would be half as bad the wireing would be the hard part as after you figured that out it would all be controled automaticly. With DC not only would you have to control the reverse loop section but you would also have to maintain each block before and after the isolated reverse loop. So in the case of DC you would be spending more times controling the blocks and reverse sections than you would be focusing on the train. Example to go thry 2 crossovers you would have to throw 2 track switches, adjust track polarity 2-4 times and then change it all back after the train made it thru and was on its way back.IMHO it will be a huge wiring issue and then trying to control it all you would have little time to watch your locos run on the layout!

 

[TomR]

Allow me to add that this is DC and not common rail. Do I need to start over and redesign this?

If you want stuff to run opposite directions at any point on the two main lines, you might want to rethink this. Since you have so many sections you could use relay logic (or multi-pole switches) to isolate a section when turning out for a bypass.

You only have a short when the two lines go opposite directions, or when you close that loop at the one end.

I am wiring my DC layout so when toggle switches are flipped to go onto sidings the main line is opened approaching the disabled direction of the turnout. You could do the same thing by opening the main line you are running into automatically. ( I use common rail.)

The problem is you really got cross-over happy. They all need insulated some way.

DCC is a lot nicer, but almost anything can be made to work with DC with a little thought and a handful of relays.

The problem depends entirely on what you want the layout to do. If the two side by side tracks run the same direction, then things are easier.

Tom

 

[TomR]

Here's how I keep stuff straight. I document it all. PITA to do but it saves major time in the long run.

http://www.w8ji.com/train_real_and_models.htm