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The layout I'm building has a double mainline and what I wanted is the appearance of a locomotive going off in the distance and returning from the same direction rather then having it circumnavigate the world. So I knew that I needed a reverse loop and since I had a double main it needed to return on the other track. Well now if you add two double mainlines then you will need two reverse loops! Now to make things really fun both mainlines "ended" in the same corner of the layout since the other corner had a large locomotive service area with roundtable. I came up with the following design which will be hidden under a mountain and not quite so symmetrical. This section will need to be automated with a built in delay.

 

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That looks interesting. I guess if you didn't want to have the tracks crossing each other you could have the two tracks on different levels. After the big discussion on derailments, I have decided to avoid turnouts and crossings on mainlines where avoidable and keep them in stations and sidings where the trains will run slowly. I should qualify this by saying this is because my preference is for fast express trains which I like to run at speed. I'm sure if you like to run your trains slowly then this would not be a problem.


It will be interesting to see how your layout develops Dennis. Please show us some pictures.
 

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I remember the layout design. Block detection to cut the track power is possible when a collision might occur.
I'm unsure how to apply block occupation to your application however. I'm sure RR&Co can easily solve this problem, you would simply need to set the permeters. This would only allow one train to enter the block at anyone time. Alternatively you could use similar wiring to that used to cut track power in a section to that used for lifting bridges. However you will need a waiting area out of sight, where trains wait until the route is safe.
 

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Discussion Starter · #4 ·
Right now I was thinking of holding them at the station before the loop. I do intend to use RR&Co software to operate parts of my railroad. I'm not sure if they cut track power though. That would seem to be the analog way of doing things plus you'ld lose the signal and not have any breaking affect. I'll have to read up more about it but I do know they handle this.

Everything I learn will be passed on. I have not written much about my track because I'm taking my time in designing it. As I ramp up I will take some pictures.
 

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What track are you planning to use Dennis ?, I've been very temped by code 83, and Tillig. When I was at the chippeningham show about 6 weeks back I spoke to International Models, I think it's a good product. The only negative was the responce from the stand about giving discounts. I thought 900ft of track was a reasonable amount to request a discount. The stand occupier thought 2 miles of track.
In that regard I might just shop for track on E-Bay if I do go Tillig.
 

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Dennis this reversing loop looks fine.

You can use it with care until you get some sort of advanced computer or automated control.

When you wire it up, isolate the track in at least 2 sections before the tunnel openings so that you can detect a train approaching, slow it down and then cut the power if required.

If you don't use block detection now, these track sections can be wired to your DCC BUS like normal. You can add the block detectors later as required.
 

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QUOTE (Dennis David @ 15 Jun 2006, 14:08) <{POST_SNAPBACK}>I'm always amazed how much knowledge there is out there.

Absolutely, I find it amazing how much some people on this forum know about electronics and model building and so on. It's good to be able to get access to all that information through this forum and the internet.
 

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An ingenious way to get both loops at the same end of the layout.

But I would definitely recommend going along with suggestions to eliminate the diamond crossings, replacing them with over/under passes. Apart from reducing potential deadspots, derailments and collision possibilities (and cash savings on the crossings), this would permit the loops to accept substantially longer trains too, though that might not bother you. Other than arranging the difference in levels, the over/underpass really does seem advantageous in several ways.

Crossing one track over another doesn't necessarily mean raising the upper level by so much. The lower track could be inset into the baseboard so that each track then shared half the height differential required and, possibly more importantly, only half the grade slope angle would be needed for each of them.

Incidentally and usefully, that arrangement isn't actually a 'reverse loop' in electrical terms. As it stands in the diagram, there is no possibility of reversal of rail polarity, which is very handy in its electrical simplicity. A reverse loop would only occur if the return loop were to re-enter the exact route from which it had originated. This could well happen somewhere else on the layout, but it doesn't happen in the diagram as shown. This is a direct result of using double main-lines instead of a single one. I have to say I like this principle a lot.
 

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Discussion Starter · #13 ·
What's not shown is I've been toying with the idea of wiring both mainlines in the same "direction" because of all of the crossing points. As far as the diamonds I'm restricted in that the layout rests on top of a 1 1/2" thick subframe that in turn rests on top of a bookcase. Because of my space requirements I could not realistically make the elevation change required.
 

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Hmm, that's a bit awkward!
But looking at the length available to trains in those loops at present - it is so very little that I feel it would be worth going to almost ANY amount of bother to avoid those two diamonds and the traffic problem they cause. it looks like 3 passenger car trains as a maximum and even that might be tight.

You could take a LITTLE bit out of the sub-frame. You could save a mm or two in height by using low profile ballast-free Peco track where it won't show, under cover there. Have you started building the baseboard yet? If not, do consider a little more depth to its frame so that your datum level track CAN drop a little when it needs to. Dennis, you just have to try to get rid of those damned diamonds, else it's going to drive you nutz and we can't have insane moderators running the joint!


Your top priority is idiot proof operation where it's all under cover.

I am REALLY worried about your wiring plans too!
Keep it simple! (as you possibly can)
QUOTE I'm taking my time in designing it. As I ramp up I will take some pictures.
Take a LOT of time thinking this over and keep that "RAMP UP" in the forefront of your mind!!!
 

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My friend you need to place this layout in it's proper context. Being a continental layout we are not happy unless we have at least a couple dozen turnouts.
I am afraid to show you the remainder of the layout less you have a heart attack.
The frame for the baseboard is done but the surface is not. Becasuse it's in my library and sitting on top of bookcases with part of it against a window I cannot block the window. So the height in that area is restricted.

As far as the diamonds, the approach to the first diamond is longer than it shows but I think I will try to do an over under instead as you suggest. Lets see if I can get enough clearance without having to result in using a rack railroad.


As far as being insane ... it's already too
 

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QUOTE I am afraid to show you the remainder of the layout less you have a heart attack.

Go on Dennis, we'd love to see it.


QUOTE As far as the diamonds, the approach to the first diamond is longer than it shows but I think I will try to do an over under instead as you suggest. Lets see if I can get enough clearance without having to result in using a rack railroad.

In the long term Dennis, I think you will thank your self for it. I can see so many problems with these crossovers, especialy if they are hidden below a hill. These problems can admittedly be prevented but you're giving yourself an awful lot of extra work for something that no-one can see. It can be a real pain in the a
e to have to rip up track and restructure when you find out it's not happening. I am still repairing over ambitious plans I had when I initially set up my layout. Which is why I'm so keen to start again with an new layout.
 

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Discussion Starter · #17 ·
I'm still not sold on having two levels. I'll need to measure how much of a incline will be required. Remember I'll need to clear the catenary as well. Maybe this calls for using a helix if I can fit that in.
In either case there will be a lot of operation before I cover anything with a mountain that's for sure.

I'll take a picture of the yard as soon as I get a couple of bits in the mail.
 

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Flyovers need lots of space - and straight line space too. They don't work too well on tight bends.

I say - use the crossovers - try it out before you build the hill and if you have problems, go on to plan B.

Automated blocks will prevent accidents. You just need well laid track to prevent derailments.
 

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QUOTE Remember I'll need to clear the catenary as well.

Are you intending to use the catenary as a power feed or is it decorative? If it is your power feed your options are limited due to the extra clearance needed. You may not have a choice.
Good luck.
 
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