Templot Club Archive 2007-2020
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posted: 3 Nov 2008 12:51 from: Gordon S click the date to link to this post click member name to view archived images |
Came across something this morning that is so basic, but I can't seem to find a solution. I want to take a turnout off a 914mm (36") radius curve, with the main line continuing straight at a tangent to the curve. I have drawn the curve and inserted the turnout, but no matter what I try cannot get the straight part of the turnout to align with the straight track. Continuing the straight plain track and overlaying the turnout shows the straight section of the turnout curves slightly and I cannot find a way of making the stright section of the turnout straight. I have tried inserting the turnout into the straight section to overcome that problem, but then find I cannot get the radius to tie up, no matter what adjustment is made to F5. I know this smacks of RTR track, but it is in a hidden section and the simplest way to deal with an issue. Apologies guys, this is so basic, but my brain has drawn a total blank...  Edit: Should have added, I watched the tutorial video on substitution radius this morning, but couldn't follow it 100%. Is that the correct video as it seemed for a much older version of the software? |
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| Last edited on 3 Nov 2008 12:58 by Gordon S |
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posted: 3 Nov 2008 13:22 from: Martin Wynne
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Gordon S wrote: I have tried inserting the turnout into the straight section to overcome that problem, but then find I cannot get the radius to tie up, no matter what adjustment is made to F5.Hi Gordon, No need for apologies, that's what we are here for. Answers I mean, not apologies!  That's the correct video. It wasn't made with version 091c, but most of it should match -- which bit doesn't seem to? Before doing F5, make sure to select action > F5 V-crossing angle options > any angle menu option. Otherwise F5 snaps to 1/4 RAM steps. In 091c you can also do action > mouse actions: real > adjust V-crossing entry straight (on a regular-type V-crossing) which gives you an extra adjustment possibility. Although for 36" radius you would probably want a curviform-type V-crossing. I will see what I can suggest for 36" substitution in 00-BF. regards, Martin. |
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posted: 3 Nov 2008 13:31 from: Gordon S click the date to link to this post click member name to view archived images |
Thanks as always Martin. I'm sure the menu items etc all function the same, it's just a little confusing when the software has been updated and it appears differently on screen. Just out of interest, why isn't the straight section of the turnout straight? Is it a prototypical issue or fundamental geometry that is fudged with RTR track? If faced with this issue, is it preferable to insert the turnout in the straight rather than the curve? | ||
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posted: 3 Nov 2008 14:41 from: Martin Wynne
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Gordon S wrote: Just out of interest, why isn't the straight section of the turnout straight? Is it a prototypical issue or fundamental geometry that is fudged with RTR track?Hi Gordon, Prototypically, at least for the common REA bullhead switches, it's not possible to have a dead straight road and a perfectly tangential curved road. If you insert a turnout in the straight track as the main road, the turnout road can't be a tangential curve. If you insert a turnout in the curved track as the main road, the turnout road can't be dead straight. Here's a picture to illustrate that. Look at the turnout below the (interesting!) signal. The main running line is the curved track, so this is a left-hand turnout, and there is a noticeable discontinuity in the diverging straight ahead road. The main lines on the left are clearly dead straight at this location, but it's not possible for the track in the foreground to be exactly parallel to them throughout. (This picture also shows a Barry slip in the yard on the right, and catch points in the diamond-crossing giving access to the yard. If the foreground line had been a running line, these catch points would have been much further back beyond the diamond.) padwood582.jpg  If faced with this issue, is it preferable to insert the turnout in the straight rather than the curve?If it's a visible section of the layout, you insert the turnout in the main running line, and adjust the size of it to get as near as possible to what you want for the diverging road. For a fiddle yard or other hidden areas where a geometrical solution is required, insert the turnout in the straight track and adjust it until the substitution radius matches the curve. regards, Martin. |
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posted: 3 Nov 2008 14:47 from: Gordon S click the date to link to this post click member name to view archived images |
Thanks again Martin. Having looked closely at the templates overlaid on plain track, I can now see the issue. Funny how these things never occur to you when using RTR track... | ||
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posted: 3 Nov 2008 20:31 from: Martin Wynne
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Hi Gordon, That was trickier than I expected. The problem is that for any standard switch, for 36" subs rad the substitution tangency point is falling within the switch front. That's easy to deal with by blanking* for a one-off, but it's not a very satisfactory solution for a standard building-block template where you want the template datum at the rail joint in the usual way. So I created a custom switch with a shorter front to match the substitution curve. Crossing angle turned out to be 1:5.22 RAM curviform. The actual turnout radius is 910mm. Box file attached below. 36_subs_00bf.png  *(peg on EGTP, do > blank up to peg) regards, Martin. |
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| Attachment: attach_393_612_36_subs_turnouts_00bf.box 194 | |||
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posted: 4 Nov 2008 13:19 from: Gordon S click the date to link to this post click member name to view archived images |
Thanks for that Martin. I have a printing question now, but will raise as a new topic. | ||
| Last edited on 4 Nov 2008 13:37 by Gordon S |
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