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Single Slip Templot Query


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Morning all,

 

I have created a single slip on my templot plan however I've now ended up with the below where the rails seem to all join in the middle of the diamond section of the crossing. Have I missed out a command somewhere along the line (excuse the pun!)

 

image.png.19354d49e5f83ac9d6f5dad829bf407c.png

 

Any help would be greatly appreciated.

Cheers,

 

Best regards and stay safe,

 

Jeremy

 

 

 

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Hi Jeremy,

 

You have (correctly) created a switch-diamond with movable K-crossings because your 1:10 crossing angle is flatter than 1:8.

 

More information and pictures in this post:

 

 https://85a.co.uk/forum/view_topic.php?id=2144&forum_id=22#p14263

 

and

 

 http://85a.co.uk/forum/view_topic.php?id=288&forum_id=1#p1587

 

cheers,

 

Martin.

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3 minutes ago, martin_wynne said:

Hi Jeremy,

 

You have (correctly) created a switch-diamond with movable K-crossings because your 1:10 crossing angle is flatter than 1:8.

 

More information and pictures in this post:

 

 https://85a.co.uk/forum/view_topic.php?id=2144&forum_id=22#p14263

 

and

 

 http://85a.co.uk/forum/view_topic.php?id=288&forum_id=1#p1587

 

cheers,

 

Martin.

 

Thanks Martin. I didn't mean to create a switch diamond but reading those posts, it appears that the largest slip diamond is 1:8. This is for my swiss layout so I'm wondering if the swiss had larger diamond slip crossings. I suppose I could just shorten the K crossings, not prototypical but would be easier in 2mm scale rather than having to add another moving part to the crossing.

 

If I were to shorten the K crossings, how would I do that?

 

Best regards and stay safe,

 

Jeremy

 

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Hi Jeremy,

 

I very much doubt that Swiss railways use fixed K-crossings as flat as 1:10, there is too much risk of wheels mis-tracking and taking the wrong route. In 00 and N gauge with wider than scale flangeway gaps that risk is greatly increased. I suggest you build it with movable K-crossings as Templot has drawn it, if you don't mind the need for two extra point motors.

 

To build it reliably as a conventional diamond with fixed K-crossings, you would need to shorten it to say 1:7 or less. That will mean re-designing the layout so that the tracks cross at a sharper angle.

 

cheers,

 

Martin.

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I came across exactly the same on my templot plan. Having looked at it in detail, I am now quite excited about constructing the movable diamond crossing.

Looking at the wiring and the need for additional point motors, I found that the wiring was simpler with the movable crossing as I had more switches and poles to play with. Meaning I didn't need to switch the diamond crossing vees all from adjacent turnouts, I could use the contacts on the diamond crossing point motors instead. I am building a double junction powered by servos and miniature relays with route setting.

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On 17/07/2020 at 09:22, ikcdab said:

I came across exactly the same on my templot plan. Having looked at it in detail, I am now quite excited about constructing the movable diamond crossing.

Looking at the wiring and the need for additional point motors, I found that the wiring was simpler with the movable crossing as I had more switches and poles to play with. Meaning I didn't need to switch the diamond crossing vees all from adjacent turnouts, I could use the contacts on the diamond crossing point motors instead. I am building a double junction powered by servos and miniature relays with route setting.

There is no difficulty with any single slip, the wiring for switching frog polarity is identical to a double slip, ie each frog is switched from the blades at the other end. It is a requirement that the interlocking prevents routes across both straight routes at the same time. Having a switch diamond does positively ensure that interlocking!

22 hours ago, Andy Reichert said:

Just be aware that any throw bar system you use should allow for the narrower than normal track gauge between the points, because the fixed end of the closure rails are converging.

Andy

Andy, I think you are confusing a single slip with something else, there is no such issue with single slips, whether fixed or movable K crossings..

Rgds.

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On 18/07/2020 at 17:54, Andy Reichert said:

Just be aware that any throw bar system you use should allow for the narrower than normal track gauge between the points, because the fixed end of the closure rails are converging.

 

Andy

 

23 hours ago, Siberian Snooper said:

Confused of Plymouth,  how can the track gauge be narrower and still allow trains to run?

 

 

 

2 hours ago, Andy Reichert said:

Off hand, I can't think of a normal railway case where trains  run "between" the point blades.

 

Andy

 

Who said they did? It's you that said that the gauge narrowed, in the first quoted post.

 

 

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On 19/07/2020 at 10:31, Siberian Snooper said:

 

 

 

Who said they did? It's you that said that the gauge narrowed, in the first quoted post.

 

 

 

I'm not sure what else you would name the distance between the point blades on a switched diamond crossing?  The tapering effect of that distance is absolutely clear on Martin's Templot example.

 

And BTW it's the subject of the OP's question.

 

Andy

 

 

 

 

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The templot illustration shows all the movable blades against the stock rails, which is conventional for a templat as its how you make the rails. But no train ever runs in that condition, the stretcher bars have to be fitted and the points adjusted. Which I'm sure you know well Andy, so why try to confuse people.

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49 minutes ago, Grovenor said:

The templot illustration shows all the movable blades against the stock rails, which is conventional for a templat as its how you make the rails. But no train ever runs in that condition, the stretcher bars have to be fitted and the points adjusted. Which I'm sure you know well Andy, so why try to confuse people.

 

Quite the opposite. I was actually trying to alert the OP to not try to use any commercial throw bars that are set to the distance required by a normal turnout. If the  double closed position of the blades shown is a template convention, then it's clearly one neither I nor the OP was aware of. 

 

 

16-6switch.gif.890b5c0d1eb32d091066c7346803d8bb.gif

 

All my US prototype drawings show pairs of points in a working position for clarity. So I follow that practice for model templates and my mention of the "points gauge" as shown above. It would seem there is a difference in conventions that neither of us was aware of and hence a two way misunderstanding. I sincerely thought I was contributing useful information to the thread, so I'm offended by what appears to be solely trolling by non-contributors.

 

I'm also contributing on the basis of actual personal experience in making working model switched diamonds in 16.5 mm gauge. Not idly speculating about "might work" ideas.

 

Andy

 

 

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I think I can see where Andy's coming from. the distance between the end of the K crossing and the movable switch will only be the flange gauge width, say 1mm, not the usual "point blade" clearance of 1.25 or whatever it is for the standard that is being used.

 

Hence the throw required would be 1mm, not 1.25mm.

 

Presumably there's a wing rail in the K crossing not shown on the template?

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38 minutes ago, roythebus said:

I think I can see where Andy's coming from. the distance between the end of the K crossing and the movable switch will only be the flange gauge width, say 1mm, not the usual "point blade" clearance of 1.25 or whatever it is for the standard that is being used.

 

Hence the throw required would be 1mm, not 1.25mm.

 

Presumably there's a wing rail in the K crossing not shown on the template?

 

Hi Roy,

 

er, no. The switch travel for switch diamonds is the same as for ordinary switches, prototype 4.1/4" = 1.42mm in 4mm/ft scale. Here's a drawing showing that:

 

switch_diamond_10bh.jpg

 

2_221106_110000000.jpg

Photo thanks to Mick Nicholson

 

For 00-SF and EM the usual setting is 1.75mm opening (the thickness of a 20p coin, used for setting). For 00-BF the usual setting is 2.0mm opening.

 

In practice no difficulty is found with any of the usual stretcher-bar designs, assuming flexible switches of course. I'm not aware of any UK switch-diamond designs having loose-heel switches. Which is not to say there are none, but in that case they may need modified stretcher bars.

 

No, there are no rails missing. Switch diamonds do not need check rails for the moving K-crossings -- see the above photo. This is a great help in constructing model slips in 00, EM, 0-MF, etc., as it is often difficult to find space for the check rails because of the overscale flange-way gaps.

 

p.s. on a K-crossing the wing rails are the outer running rails, with a bend in the middle, as shown on the drawing.

 

cheers,

 

Martin.

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image.png.2190fef1c0b1e854b95acdf46787f049.png

 

Looking at the drawing Martin posted, There are two stretcher bars on the LH pair of point. The second bar slightly further from the points end has to be shorter that the end one.  I also think it's highly probable that even the end bar is slightly shorter than that for a normal turnout, since it's not completely at the full track gauge base of the triangle section formed by the points when closed.

 

Andy

 

 

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Actually there are 3 stretcher bars shown on the left set of switches and 2 on the right set, they should both be the same and I suspect one has been accidentally omitted from the drawing. Of course the length of each stretcher has to be set for its location. The switch diamond is no different in this respect from any other switch.

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Just be aware that any throw bar system you use should allow for the narrower than normal track gauge between the points, because the fixed end of the closure rails are converging.

Now you have explained what you were getting at it does make a sort of sense! The use of 'track gauge' caused confusion, replace those two words with 'distance' and we might well have understood.

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All is clear now, I realised that there's no check rail in the middle of the K crossing on the switched diamond, hence my comment. Interesting to see both sides of the switch rail are planed.

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4 hours ago, roythebus said:

All is clear now, I realised that there's no check rail in the middle of the K crossing on the switched diamond, hence my comment. Interesting to see both sides of the switch rail are planed.

 

Both sides of all switch rails are always planed and the centre web bent to provide the maximum strength all the way to the tip.  It's more obvious on flat bottom rail than bullhead, as the base protrudes more visibly.

 

Modelling that in FB rail is a challenge. I use CNC machining to make mine in 3.5 and 4 mm scales.

 

Andy

 

 

 

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