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topic: 3137help with crossovers on transition curves
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posted: 26 Nov 2017 21:28

from:

madscientist
 
 

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Im having a little issue with " make ordinary crossover " on a transition curve.  Specifically turnout 23 below, This is made the control and the crossover is generated .  What I do find is the crossover turnout so created is not exactly parallel to the exit track , i.e. if I extend the approach track it does not exactly run parallel to the exit of the initial  crossover turnout.  despite the screen shot the tracks are all connected accurately 
the next step is to make the short exit track of the crossover bottom left, straight , doing this shows up that the loop straight line is not aligned with the crossover straight ( K is 0.57 ) 

box file attached 


thanks as always 
3004_261617_520000000.png3004_261617_520000000.pngjust to add, after the crossover is created I can go in to " Geometry - Straight" and this creates a straight track and removes the transition , but then I have to rotate the turnout on Peg 5 position to get the K = 180 ( if you follow me ) , but isnt that creating a little kick at the peg 
Attachment: attach_2583_3137_club0gauge.box     199
Last edited on 26 Nov 2017 21:48 by madscientist
posted: 26 Nov 2017 22:00

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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Hi Dave,

It is not mathematically possible for two transition curves to be exactly "parallel" within the transition zones.

This means that it is not possible to fit a crossover with both turnouts exactly aligned at their CTRL-5 mid-points (which is what the make crossover tool does).

If you do that on a transition curve, you get a warning that the new transition curve may need adjustment to achieve the desired alignment.

If as in your plan it is important that the new track is parallel/concentric with the original track (beyond the transition zones), do this instead:

1. on the first turnout do geometry > turnout-road exit length > crossover.

2. do tools > make double-track TS. Without a crossover to consider, Templot can do an automatic adjustment on the new transition zone position. Select the automatic option.

3. insert a turnout in the new plain track, and swap it facing-trailing (CTRL+N).

4. do geometry > turnout-road exit length > crossover again.

5. then roam it into the required position with its turnout road aligned with the first turnout (CTRL+F9 mouse action). Zoom in to see it. There will likely be a slight overlap.

6. if necessary you can adjust the length(s) of the turnout road(s) using the CTRL+F12 mouse action.

regards,

Martin.

posted: 26 Nov 2017 22:21

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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p.s. Dave,

You have barely any running clearance on those curves:

2_261719_140000000.png2_261719_140000000.png

The track spacings need widening a fraction. There is a video showing how to do that with the dummy vehicle, see:

 http://flashbackconnect.com/Movie.aspx?id=5TKjRjhcaeHNM176Xf2xUg2

Martin.

posted: 27 Nov 2017 13:45

from:

madscientist
 
 

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thanks martin

I actually followed the sequence you laid out when I was designing this layout , that is I created two complete ovals representing the Up and Down lines with transition curves ( easement to straight ) on the curves

Then I inserted the turnout and then created a " ordinary crossover"

This works fine where the other crossover is also on the transition

However in this case of the " loop " line, the crossover is too a straight track

in this case I find the toe of the turnout does not align correctly and the K is not 180 ( or 0) but 0.07 etc , i.e. off by a bit

By the way is there any way to speed up the tedious process of correcting lengths, I use snap features sometimes as I keep forgetting what all the peg acronyms mean ( a drawing would be useful to print out by the way!)

Thanks re clearances, 80mm was the number given in the Gauge 0 manual, it seems a little tight alright

time to start version 2 ( as I discovered that in practice I cannot have curved crossovers on 6'foot radius main lines without severe radius reductions in the crossovers ( face palm)

posted: 27 Nov 2017 14:01

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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madscientist wrote:
in this case I find the toe of the turnout does not align correctly and the K is not 180 ( or 0) but 0.07 etc , i.e. off by a bit
Hi Dave,

If you follow the sequence I posted in my previous reply, it won't be off.

By the way is there any way to speed up the tedious process of correcting lengths
See the extend/shorten to meet functions:

 http://templot.com/companion/link_existing.php

regards,

Martin.

posted: 27 Nov 2017 19:49

from:

madscientist
 
 

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Martin I have another issue

On occasion when using extend shorten, I get a "inaccuracy error " message ,i.e. with an option to go ahead anyway , I know its a tiny thing , but I cant see how I am generating these alignment issues in the first place

any pointers ?
PS thanks for the tips on transition crossovers, I created the blank plain tracks first and the crossovers aligned as yu say 


cheers

dave
Last edited on 27 Nov 2017 19:50 by madscientist


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