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posted: 28 Mar 2011 13:54 from: Raymond
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Simply as an exercise to see if I could do it, I have tried to produce a double track crossover. The basics were not difficult but the check rails were somewhat complex resulting in many partial templates. Anyone with more knowledge than I care to comment on its viability? Regards Raymond Be an idea to add the box file!! |
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Attachment: attach_1012_1434_double_junction_5.box 337 | |||
Last edited on 28 Mar 2011 13:55 by Raymond |
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posted: 28 Mar 2011 16:20 from: mike47j click the date to link to this post click member name to view archived images |
As someone with less knowledge that you, I don't see the point of the check rails with names like check3, check3a, check5, check5b. In the GWR switch and crossing practice book, these are opposite a central frog, but in your case they are away from that frog. Mike Johnson |
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posted: 28 Mar 2011 17:26 from: Raymond
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Hi Mike, There has to be some form of name or finding them to work on among lots of 'no-name' would be irksome. Not sure what you mean about the positon of the check guards but looking at the picture on page 91 I think the crossing angles and the fact mine is on a curve would make some differences. Regards Raymond |
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posted: 28 Mar 2011 18:15 from: mike47j click the date to link to this post click member name to view archived images |
Sorry, for the ambiguous question. Its not the names that I have a problem with, its the check rails. They seem to serve no purpose since they are not opposite the frogs. After a quick experiment I think its the increased separation of the tracks that is the main cause of this. The angle and curvature don't seem to have much effect. Before,I did not understand note 2 on page 91 as its does not appear relavant to the diagram. However, in your diagram it clearly is relavant as many of your wing rails are also check rails for other frogs. Mike Johnson |
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posted: 28 Mar 2011 18:18 from: Paul Boyd
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Hi Raymond it must be the season for scissor crossings! Have a look at the thread topic 1406 and you'll see how I've done it. Basically, loads of partial templates... Don't look too closely at the timbering! There's no right or wrong way to get the same end result, and as it's the end result that matters, who cares how you get there? |
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posted: 29 Mar 2011 00:42 from: Ian Allen
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Raymond, Here is a scissor crossover still being worked on by myself. As you can see I have temporarily removed 4 check rails until such time as I build up separate templates. Ian |
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Attachment: attach_1024_1434_Coulsdon_Scissor_11_03_29_0010_29.box 306 | |||
posted: 29 Mar 2011 07:44 from: Raymond
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Hi Ian, Why have you chosen four different crossing angles, are you following prototype plan? Regards Raymond |
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posted: 29 Mar 2011 09:37 from: Les G click the date to link to this post click member name to view archived images |
Raymond wrote: There has to be some form of name or finding them to work on among lots of 'no-name' would be irksome. An ambitious effort Raymond, well done; you are well ahead of me in your mastery of Templot. My current level of understanding of formation geometry comes from study of LNER practice. [Standard railway equipment-permanent way 1926, from NERA ] I do not have the GWR publication. You asked for comment, so here goes. The check rails at 700-75; 700-160; 1060-140; and 1050-200 do appear to be redundant in the formation as pointed out by Mike 47j. Clicking on "26.check5a", I note that only half of the check rail is high lighted. This suggests that these check rails appear as a result of using multiple templates rather than from prototype practice. ie The redundant common crossing they protected has been removed during the cut and paste process but leaving the check in place. I see that there are guide lines associated with checks 3a,and ?; 5 and 5a which converge to positions between the roads, were these a part of your original setting out? I assume there is a means to eliminate unwanted elements from the drawings, but I have yet not got that far in my study, thankyou for sharing your progress. regards Les G |
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Last edited on 29 Mar 2011 18:44 by Les G |
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posted: 29 Mar 2011 11:09 from: Ian Allen
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Raymond wrote: Hi Ian, Hi Raymond, The different crossing angles allow the trackwork to be designed so that the curves flow more smoothly through the scissors and to maintain curving radii above a 6' minimum. I was also conscious of not wanting stock to lurch through the crossing. On the prototype, there were many instances of pointwork being designed and built to fit a specific location when "stock" parts wouldn't fit or suffice. Ian |
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posted: 29 Mar 2011 11:17 from: Stephen Freeman
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There do as Les says, appear to be some redundant check rails. The diamond vees are perhaps a little too opposite to the turnout vees, which could result in a 'double drop' best to be offset a little. | ||
posted: 29 Mar 2011 13:17 from: Raymond
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I'll take another look at them but the check rails are present in GWR practice so need to be present on the model. They are made up from multiple templates and fitted by eye so the centre lines may well look off. Regards Raymond (Not Ray please) |
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posted: 29 Mar 2011 13:51 from: mike47j click the date to link to this post click member name to view archived images |
I'm not convinced that those check rails were always present, the picture on page 56 has some but not all. I think the key to not getting 2 v crossings inline with wider track spacing, is to offset the diamond as in that photo. Mike Johnson |
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posted: 29 Mar 2011 16:10 from: Raymond
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mike47j wrote: I'm not convinced that those check rails were always present, the picture on page 56 has some but not all. Thanks for that Mike. I have revisisted it in the light of your comments and that picture and, starting from scratch, redrawn the whole thing asymetrically and it seems to work. Here are the tracks. I have yet to add timbers but that is easy enough. This took a couple of hours whereas the first one took days. Regards Raymond |
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Attachment: attach_1027_1434_double_junction_6.box 283 | |||
posted: 29 Mar 2011 16:22 from: Stephen Freeman
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I think you need a few check rails as well. Have a look at scissors on my website |
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Last edited on 29 Mar 2011 16:24 by Stephen Freeman |
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posted: 29 Mar 2011 17:15 from: Raymond
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Borg-Rail wrote: I think you need a few check rails as well. Have a look at scissors on my website Thanks Stephen, I make it two required, extended wing rails and I think that covers everything. Now the timbering is done as well. Regards Raymond |
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Attachment: attach_1028_1434_double_junction_7.box 257 | |||
posted: 29 Mar 2011 20:23 from: mike47j click the date to link to this post click member name to view archived images |
Sorry. I think you need one more. The diamond V crossing on the right does not have a check rail above it. Mike Johnson |
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posted: 30 Mar 2011 09:00 from: Raymond
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mike47j wrote: Sorry. I think you need one more. The diamond V crossing on the right does not have a check rail above it. Then if so, it needs at least one more at the other end. Whether similar would be needed at the other two sides I don't know but pictures in "Switch & Crossing Practice" suggests not. Anyway, I have found a way more accurately to fit these fiddly things in place as here. My thanks to everyone for their invaluable (as always) help. Regards Raymond |
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Attachment: attach_1029_1434_double_junction_8.box 254 | |||
posted: 30 Mar 2011 14:56 from: Les G click the date to link to this post click member name to view archived images |
Hi Raymond, It is my observation that check rails are used opposite crossing vees to eliminate the risk of sideways movement of the wheel axle resulting in derailment. It follows that having a formation where vees are exactly opposite would result in rough running or a derailmant risk due to the lack of lateral contraint of the axle. Mike Johnson drew attention to the the right hand diamond crossing, logic suggests that you are right, and there should also be one on the other side of it. Extending the wing rail of crossover 4 would probably do the trick. Again, Thankyou for sharing Les G |
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