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topic: 2913how do I fit a curve between two straights?
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posted: 20 Aug 2016 23:37

from:

DavidLaing
 
Edinburgh - United Kingdom

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Hopefully this is a straightforward question: how do I fit a curve between two straights?
In the attached plan (which is 4-SF), I have three tracks to the left which are at 50mm centres – these will enter a fiddle yard and represent from top to bottom: an Engineer’s siding; a freight arrival / departure loop (originally the down line); and the current single track branch line (originally the up line).  To the right are four tracks which are from the top: an Engineer’s siding (previously access to the former Goods Yard); Platform 3 (the former down through platform); Platform 2 (the former up through platform); and Platform 1 (a bay platform).
Starting at Platform 3 on the right, I need the toe end of the turnout to cross the baseboard joint at 90 degrees and since I am using pre-assembled common crossings from C&L (which are straight), I think this turnout is ‘final’.  If I reduce the radius any further then the diverging radius drops below 36 inches and I have a transition of zero length between this curve and the common crossing.  I have then made an ordinary crossover at 44.67mm centres, which should provide the access to Platform 2.  I’m not sure why it stops short of the baseboard edge at 980mm, but it’s not critical as this will be flexi-track.
Jumping to the mainline from the fiddle yard (ie on the left), I have fitted a short straight and then a constant radius curve to the common crossing and again a straight through the common crossing.  However, I have only selected this radius through the leftmost turnout by eye to get it to line up with the turnout to Platform 2.  Is there a way to get Templot to connect these two turnouts?  That is, I don’t want to move the middle turnout and I want the leftmost turnout to remain pegged to the approach straight.
I’ll have to do the same with my freight arrival departure loop and Platform 1 approach, so I need to know how to do this.
Thanks
Davidundefinedundefinedundefinedundefinedundefinedundefined
Attachment: attach_2320_2913_Dungrange_v2008.box     264

posted: 21 Aug 2016 00:08

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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However, I have only selected this radius through the leftmost turnout by eye to get it to line up with the turnout to Platform 2.  Is there a way to get Templot to connect these two turnouts?  That is, I don’t want to move the middle turnout and I want the leftmost turnout to remain pegged to the approach straight.
Hi David,

Welcome to Templot Club. :)

Extend some approach track on the middle turnout (F3), split it off from the turnout and then curve it to just clear the straight track on the left. Use the make transition function to link the templates, adjust the boundaries, and then insert the turnout in it. Then roam (CTRL+F9) the turnout into position.

Can you follow that or do you need a bit of video?

Have we not already covered this on RMweb? at:

 http://www.rmweb.co.uk/community/index.php?/topic/112509-designing-an-s-curve-crossover-in-templot/

regards,

Martin.

posted: 21 Aug 2016 10:56

from:

DavidLaing
 
Edinburgh - United Kingdom

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Martin,

Yes, we have covered this before, thanks, but I seem to be going wrong at the 'Make Transition' stage. Which template should be the control at this point? If I have the newly created constant radius approach curve as the control template, go to 'Geometry' and select 'Transition Curve' then I end up changing my new constant radius curve to a transition curve, which is pegged at the right end, but this doesn't link to the straight on the left other than adjusting the transition curve parameters by eye. Is there another 'Make Transition' function that I am missing?

posted: 21 Aug 2016 12:31

from:

Martin Wynne
 
West Of The Severn - United Kingdom

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DavidLaing wrote:
Is there another 'Make Transition' function that I am missing?
Hi David,

Yes.

I have made a bit of video for you. Sorry it is so scruffy but a smooth edited video takes hours to produce.

If you click the file attachment below it should play on your system in the Templot Video Player.

If not you can watch it in much poorer quality here:

 http://flashbackconnect.com/Default.aspx?id=kjP0S_X4RrdDyP0Hs7eJrw2

edit: At the end of the video I should have changed the inserted turnout to a curviform V-crossing before making the branch track from it in this case. Sorry about that.

The make transition function is described in this tutorial -- it is a very old page but still essentially valid:

 http://templot.com/martweb/info_files/make_trans.htm

regards,

Martin.
Attachment: attach_2321_2913_clip18.fbr     253

posted: 21 Aug 2016 12:39

from:

Phil O
 
Plymouth - United Kingdom

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Welcome David

I have had a quick shufti at your box file and as it stands you will be unable to make a transition curve as you have currently drawn it.

I suggest you make a branch track from the Mainline Approach Turnout and curve it towards the bottom of the page the radius is not critical, store and background now select the trap point road and curve it upwards so that the curve is not forming a tangent and then click on you branch track. The menu that appears on the left has a peg align menu, click on that and select make transition curve from control template and select that and then select one of the other two options left or right. See the screen shots.

Phil

posted: 21 Aug 2016 12:44

from:

Phil O
 
Plymouth - United Kingdom

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38_210743_550000000.png38_210743_550000000.png
Phil O wrote:
Welcome David

I have had a quick shufti at your box file and as it stands you will be unable to make a transition curve as you have currently drawn it.

I suggest you make a branch track from the Mainline Approach Turnout and curve it towards the bottom of the page the radius is not critical, store and background now select the trap point road and curve it upwards so that the curve is not forming a tangent and then click on you branch track. The menu that appears on the left has a peg align menu, click on that and select make transition curve from control template and select that and then select one of the other two options left or right. See the screen shots.

Phil


posted: 21 Aug 2016 12:45

from:

Phil O
 
Plymouth - United Kingdom

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Number 238_210744_490000000.png38_210744_490000000.png

posted: 21 Aug 2016 12:47

from:

Phil O
 
Plymouth - United Kingdom

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Number 3

choosing the left hand option first

38_210746_240000000.png38_210746_240000000.png

posted: 21 Aug 2016 12:50

from:

Phil O
 
Plymouth - United Kingdom

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and finally.

Delete the unwanted templates and shorten the new one to fit and then redo the catch point.

HTH

Phil38_210748_420000000.png38_210748_420000000.png



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