reversing loop - will this work

[notlob]

Hi all

 

as a newbie - returning after a few !! years out of the hobby, I need a little help with an idea

 

is it possible to create a continuous run but also have it as 2 reversing loops?

 

so i want to have a squashed oval to create the 2 loops but instead of these being at different levels make them into a combined loop on the same level

 

so what i was thinking was i need the attached rough sketch

 

is this viable? and can anybody do a sketch of the point work in templot so I could attempt to build it?

 

 

 

[Ray H]

Is it on a DC or DCC controlled layout?

[notlob]

Hi Ray

 

It will be DC to start, maybe down the line i will try DCC

[notlob]

the attached is what i was thinking - excuse the bad drawing - done in paint 

[Ray H]

Do you want the trains to traverse the return loops without stopping?

 

I believe it would be simpler (but not necessarily cheaper) to implement something like this in dcc using some add-on kit.

 

I'd suggest that you need to isolate the two back to back points (and any track in between) from the rest of the wiring and feed that section of the layout with a switch that would reverse the running rail polarity (relative to what it had been) depending upon the move actually being made. The isolated section need only be short if you were more than 100% certain that you were never going to have trains with more than one loco. Some of the more modern multiple units have pick-ups on more than one coach so you'd need to ensure that the isolated section was long enough to accommodate the extremities of such trains.

 

I think you may find that it is not possible with DC to traverse the return loop without stopping - but someone will now prove me wrong!

 

Can I suggest that you try and learn Templot yourself? You'll then be able to make changes as a matter of routine without needing to keep fielding questions from someone else who you've asked to draw up the plan. You'll probably find people will be happier to answer specific question to help you than they will be to produce the plan. After all, you'll presumably need Templot output for the rest of the layout as well.

[JDW]

Hi,  

 

I think there are people who will be able to better answer your question than me in terms of electrics.  However, may I suggest that in terms of trackwork, you could make it much simpler and keep all of the features. 

 

EITHER:  Replace the two points on the bottom right of the circle with a diamond crossing.  This will still allow trains from either side to exit either side, but would give you two interlaced loops rather than two interconnected ones.  Electrically, that would mean that you just had to wire each as a return loop.  Since trains will be going from one track to another, exactly how you do this on DC will depend on the rest of your layout, but should be simple enough with a few isolating sections.  

 

OR: to simplify the trackwork, you don't NEED the inner of the two "main lines" in the top left corner.  You can delete this line, trains entering top right going to bottom left can just as easily go via the bottom right part of the circle.  This would mean keeping the two loops linked with points but would get rid of the two diamond crossings on your plan.  You'd still have the same flexibility as your plan, but with less trackwork, as you couldn't have trains using both at the same time anyway.

 

I can't attach a drawing, but hope that makes sense!

[crazynitwit]

Hi all

 

as a newbie - returning after a few !! years out of the hobby, I need a little help with an idea

 

is it possible to create a continuous run but also have it as 2 reversing loops?

 

so i want to have a squashed oval to create the 2 loops but instead of these being at different levels make them into a combined loop on the same level

 

so what i was thinking was i need the attached rough sketch

 

is this viable? and can anybody do a sketch of the point work in templot so I could attempt to build it?

Ideally you would have one return loop at one end with another on the opposite with a line (or two) in the middle maybe leading to a station or a couple of industries.

[notlob]

Ideally you would have one return loop at one end with another on the opposite with a line (or two) in the middle maybe leading to a station or a couple of industries.

yes but i wanted a continuous run - to watch the trains go by - and a return loop when i want them to go to, and come back from somewhere

 

JDW - thanks for the input - and yes it might be simpler to lose the inner road and the 2 points

 

Ray - will look into the Templot tutorials, but the rest of the layout will probably use peco/Hornby points for simlicity

 

thanks to you all for your feedback

Edited November 11, 2017 by notlob

[crazynitwit]

yes but i wanted a continuous run - to watch the trains go by - and a return loop when i want them to go to, and come back from somewhere

 

JDW - thanks for the input - and yes it might be simpler to loose the inner road and the 2 points

 

Ray - will look into the Templot tutorials, but the rest of the layout will probably use peco/Hornby points for simlicity

 

thanks to you all for your feedback

Two reversing loops would give you continuous run. I know a diagram would be helpful but I don't have any plans at hand.

[notlob]

Two reversing loops would give you continuous run. I know a diagram would be helpful but I don't have any plans at hand.

I understand what you are saying

 

but I was looking to have a circuit of the loft without having to do gradients i.e. 1 return loop above the other

so yes i could have 2 return loops and that would create a continuous run but i wanted to be able to do a continuous run round and round, and also have the ability to go somewhere and return from said somewhere!

[BG John]

yes but i wanted a continuous run - to watch the trains go by - and a return loop when i want them to go to, and come back from somewhere

 

JDW - thanks for the input - and yes it might be simpler to loose the inner road and the 2 points

 

Ray - will look into the Templot tutorials, but the rest of the layout will probably use peco/Hornby points for simlicity

 

thanks to you all for your feedback

If you're using Hornby or Peco for the rest of the layout, I don't think you'd get any benefit from handbuilding track using a Templot plan. I've drawn it in SCARM using Peco Set Track, plus a bit of flexi track, and I don't think you'll do better than this. I've used 1st radius curves and it takes up four feet. Use a larger radius and it would obviously be bigger. If you wanted the track as you drew it, you'd need a larger radius for the outer track, and the diamond crossing would make it even bigger. I'm assuming your trains will go round 1st radius curves!

 

I used flexi track for the curves from the double track, which I set at normal Streamline spacing. The Set Track loop doesn't quite join up in SCARM, but presumably would in real life. I'd attach the SCARM file if I was allowed to. If you want it, PM me your e-mail address.

 

[notlob]

If you're using Hornby or Peco for the rest of the layout, I don't think you'd get any benefit from handbuilding track using a Templot plan. I've drawn it in SCARM using Peco Set Track, plus a bit of flexi track, and I don't think you'll do better than this. I've used 1st radius curves and it takes up four feet. Use a larger radius and it would obviously be bigger. If you wanted the track as you drew it, you'd need a larger radius for the outer track, and the diamond crossing would make it even bigger. I'm assuming your trains will go round 1st radius curves!

 

I used flexi track for the curves from the double track, which I set at normal Streamline spacing. The Set Track loop doesn't quite join up in SCARM, but presumably would in real life. I'd attach the SCARM file if I was allowed to. If you want it, PM me your e-mail address.

 

Reverse Loop with Peco Set Track.png

thanks, that looks like what i wanted to achieve

 

will try to create it on a test board

[Michael Edge]

To run round a reverse loop with DC control is quite easy, a section of the loop is fed through diodes. This only allows the current to flow one way, while the loco is on this section reverse the controller, the loco will continue in the same direction - which will be correct when it gets off the reverse loop. 

[sp1]

To run round a reverse loop with DC control is quite easy, a section of the loop is fed through diodes. This only allows the current to flow one way, while the loco is on this section reverse the controller, the loco will continue in the same direction - which will be correct when it gets off the reverse loop.

How would the diodes be wired in?

[notlob]

To run round a reverse loop with DC control is quite easy, a section of the loop is fed through diodes. This only allows the current to flow one way, while the loco is on this section reverse the controller, the loco will continue in the same direction - which will be correct when it gets off the reverse loop. 

this is for a single track reversing loop I guess. what I meant/require is the squashed oval to simulate double track, so the current doesn't change polarity at all

[JDW]

As far as I can see, there isn't really a "reverse loop" here in electrical terms at all, assuming that the twin track circuits aren't connected by a crossover for example.  I'm assuming that the two tracks that disappear bottom left go around the room and back to the top right.  That being the case, assuming they remain separate, there should be no need for special wiring.  Imagine  train heading up from bottom left.  The left wheels will always be on the left rail whatever way it arrives and leaves and returns - i.e. the outer rail of the outer line and circle, but beware that if you have separate controllers for the two circuits when the reverse loops aren't in use, you would need to wire one the opposite way, so that the red wire (for the sake of argument) is always to the left hand rail in normal running on either track.  However, if you put a station on the opposite wall, with crossovers etc, then you would need to treat them as return loops in the electrical sense. 

[Dunsignalling]

thanks, that looks like what i wanted to achieve

 

will try to create it on a test board

Be extremely cautious about using 1st radius track, its suitability depends very much on what you want to run.

 

Almost all medium/large r-t-r locos (and some coaches) made nowadays demand 2nd radius and some don't seem entirely happy on that. With this having effectively become an industry norm, the logic of the manufacturers continuing to produce 1st radius curves must be open to question.

 

Such limitations are more likely to increase than disappear, so I'd be reluctant to build-in a self-imposed restriction.

 

In any case, r-t-r points are 2nd radius, so everything is likely to line up better if you make it all 2nd radius.

 

John

Edited November 12, 2017 by Dunsignalling

[BG John]

I used 1st radius to see what the minimum possible size was. I didn't say it would work . It's up to the OP to experiment, which is what I think he's going to do.

 

It's a nice idea, and a shame I haven't got anything suitable planned to try it on. I'd use radio control to avoid having to work out the wiring though .

[notlob]

 

In any case, r-t-r points are 2nd radius, so everything is likely to line up better if you make it all 2nd radius.

 

John

Thanks to BG John's Scarm layout diagram I downloaded Scarm and it works very well with Hornby 2nd radius curves - the 2 returns are flexible track

Edited November 12, 2017 by notlob

[JDW]

Of course, the only problem now is that this takes up a lot of space.  i suggest you buy lots of DMUs instead, they don't need to turn around 

[notlob]

Of course, the only problem now is that this takes up a lot of space.  i suggest you buy lots of DMUs instead, they don't need to turn around 

 

thats doubtfull 

 

its only just over 4ft so will fit in a far corner of the loft - leaving 3 other corners to fill with more interesting stuff!

[notlob]

It's a nice idea, and a shame I haven't got anything suitable planned to try it on. I'd use radio control to avoid having to work out the wiring though .

now are you saying that nobody else has put this forward as a solution to the squashed oval all on 1 level?

 

Having perused many plans from Mr Freezer both in RM as youngster and the many 'Plans for xx' books he published, I wanted to do the squashed oval but didn't want the multiple level issues as a  flat board is more to my skill level  - at the moment   but still wanted the round and round tail chaser for the Grand kids to watch

Edited November 12, 2017 by notlob

[John ks]

Notlob

 

Here is a slight modification to your plan

It eliminates the S curves on the inner loop & will make for smother running, downside is it takes up more real-estate.

 

You will need insulated joiners where the red spots are. (this will only work with insulfrog points)

 

If you use DC with separate controllers (the controllers must be feed from separate transformers) then to traverse the return loop set both controllers to the same speed and direction, set the appropriate points & drive through

 

If you are using DCC or block switches then it can get complicated

 

The A B, a b on the drawing show the polarity from each controller if you are going to follow JDW.s post. Remembering that any crossovers elsewhere between the mail lines will have to be treated like return loops

 

 

If any body can see any flaws in the above please let me know

 

John

 

 

 

 

 

[DCB]

That looks like the problem I had with my loft layout, similar concept nearly impossible to make work. John KS plan works with steam rank locos, however lots of diesels and steam tender locos have pickup one side of the loco and one side of the tender or one side leading bogie the other side trailing and wont get across the join between two separate transformers.

 

The easiest way to make the loop work is with common return cab control with the common rail the right hand rail, so with double track the rails adjacent to each other are common return. 

 

With this and insulfrog points you don't need isolators.

 

This is fine until you introduce crossovers between the two tracks at which point you need to abandon common return and switch both -ve and +ve feeds, however stopping to switch controllers before running across a crossover is easier than trying to do it half way around a return loop..

Edited November 13, 2017 by DavidCBroad

[BG John]

now are you saying that nobody else has put this forward as a solution to the squashed oval all on 1 level?

 

Having perused many plans from Mr Freezer both in RM as youngster and the many 'Plans for xx' books he published, I wanted to do the squashed oval but didn't want the multiple level issues as a  flat board is more to my skill level  - at the moment   but still wanted the round and round tail chaser for the Grand kids to watch

I've no idea. All my various layouts are of the small end to end terminus - fiddle yard type. I've had ideas for a big 4mm scale P4 broad gauge layout though, where your idea could be perfect, if it wasn't likely to take up half the room to get the large radius curves in!