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Single Slip verses Double Slip Turnouts

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Single Slip verses Double Slip Turnouts
Posted by railandsail on Thursday, December 06, 2018 10:09 PM

Would anyone mind giving me their thoughts about using a single slip turnout rather than a double slip one,...positives vs negatives.??

I have in mind a place where I think the single slip would be advisable over a double, but before descrbing my particular situation I was looking to hear generalities about the two.

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Posted by NeO6874 on Friday, December 07, 2018 6:59 AM

For all intents and purposes, slip switches are crossings that're made up of a pair of turnouts (single-slip) or two pairs of turnouts (double-slip).

If you have some track on hand, you can make your own "model" of a slip switch pretty easily, by using two turnouts (1 each left and right-hand) of the same frog number (e.g. 6). 

  1. set the first turnout down on your table / workbench, oriented so that the through track is heading east/west. 
  2. Take the other turnout, and orient it such that the two diverging routes overlap as perfectly as possible (this may not work that well).
  3. Done - a train can now head east/west or north/south through the crossing, and depending on the orientation of the diverging routes, one of these "slips" will be possible:
  1. East -> South (E/W is RH, diverging eastbound & N/S is LH) or North -> West
  2. East -> North (E/W is LH, diverging eastbound & N/S is RH) or South -> West
  3. West -> South (#1, but diverging westbound) or North -> East
  4. West -> North (#2, but diverging westbound) or South -> East

A double-slip is effectively options 1 and 3 or options 2 and 4 laid over each other.

-Dan

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Posted by cx500 on Friday, December 07, 2018 8:41 AM

The railroads preference is the simpler (and cheaper) the better.  That is why slip switches are only found where there is absolutely no alternative.  A single slip switch is simpler than a double slip switch, so if that is all that is needed, that is what is installed.  In practice they were comparatively rare.

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Posted by 7j43k on Friday, December 07, 2018 9:15 AM

Paralleling the above statement, if a railroad determined that the "other" route would not be (or "rarely") used, then a single slip would be installed.

 

Ed

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Posted by selector on Friday, December 07, 2018 12:32 PM

A single slip switch is a combination of a one-way crossing, depending on direction of movement, and a turnout to afford directional change onto only one route, depending on direction of movement.  So, intended traffic patterns matter there.  Where trains moving in one direction must not be permitted to encounter other rail traffic, but may 'slip' onto an adjacent parallel route, the single slip works...again, in the one direction. 

A double slip comprises TWO crossings, both directions of movement, plus two slips permitting access to (proximally) two parallel tracks on either side of it.  They would be found in terminal yards with no through traffic, such as a passenger terminal where trains must return from whence they came in order to join the main line(s), or continue in the same direction if it's a through terminal.  They permit various access to the 'throat' comprising two or more parallel leads that eventually lead to routes going in several directions to several destinations. 

Contrary to common opinions, such slips are rather frequently seen, especially still in Europe, and most frequently at stations with multiple tracks and multiple routes where trains must be shunted across several parallel tracks in succession, but allowed to join any one of them if that is to be the train's defined path for ingress and egress.

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Posted by richhotrain on Friday, December 07, 2018 1:14 PM

railandsail

Would anyone mind giving me their thoughts about using a single slip turnout rather than a double slip one,...positives vs negatives.??

I have in mind a place where I think the single slip would be advisable over a double, but before descrbing my particular situation I was looking to hear generalities about the two. 

Brian, why not just describe your particular situation and tell us why you think the single slip would be advisable over a double slip.

I have four Peco Code 83 double slips on my layout and one Walthers Shinohara Code 83 double slip.  There were situations where I would arguably be able to use a single slip, but I still chose the double slip because it is more versatile and therefore preferable to the more limited function of a single slip.

Perhaps more importantly, there is usually no difference in cost between a single slip and a double slip. 

I can tell you this. The operation of a double slip is complicated whether it be operated manually or electronically. That said, once you get the hang of it, operation of a double slip becomes somewhat intuitive.

On the prototype, slips were mainly used when and where space was limited such as in yards and larger stub end passenger station tracks.

Rich

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Posted by BigDaddy on Friday, December 07, 2018 5:05 PM

Rich, I was going to email you, but why not make my question public?  Can you post a couple pics of your double slip switches?

I bought one thinking I could make a double crossover in a smaller footprint and that was a flawed idea for a couple reasons.  So I am trying to figure out how to best utilize it.

Henry

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Posted by richhotrain on Friday, December 07, 2018 7:33 PM

BigDaddy

Rich, I was going to email you, but why not make my question public?  Can you post a couple pics of your double slip switches?

I bought one thinking I could make a double crossover in a smaller footprint and that was a flawed idea for a couple reasons.  So I am trying to figure out how to best utilize it. 

On my newly built layout, I have a series of four Peco Code 83 double slip switches that allow trains to access any one of four mainline tracks from either direction.

P1010530.jpg

Here is a closeup of one of the Peco Code 83 double slip switches.

P1010515.jpg

These are spring loaded switches that I operate with a flip of the finger against the point rails.

Rich

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Posted by BigDaddy on Friday, December 07, 2018 9:03 PM

Thanks Rich

Henry

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Posted by railandsail on Saturday, December 08, 2018 9:53 AM

Single or Double Slip Turnout

 

So here is my particular situation. I have two spur lines off of the mainlines feeding my peninsula area. It is desired that these 2 entering lines be able to select between either of 2 lines themselves. The most 'compact' manner to do such a thing is a slip switch.

A single slip switch accomplishes just what I want to do,...take the entering train and curve it around onto the same side, or cross it over to the other side. It does this in one single selection of the controller. It can remain on one single selection and do the same thing for trains entering from either track,...cross them over, or leave then curving around on the 'same track'.

Another nice feature of the single slip is that should the train stop, then get reversed while over this turnout, the train will NOT try to pick the opposite track and derail,,,as it might well do on a double slip switch. Is my thinking correct??

Since the double slip switch has 'another set of point rails' at its other end, that ARE NOT always set in the correct position, the train could well back up and try to chose a different route than it came in on. In other words it requires 2 control settings to get the dbl-slip to act in the manner I seek above, ….plus when I change the incoming route I have to make TWO selections to get it to operate like the single slip that I did not have to make any new selections.??

 

 

Overall view (sorry, still just a paste in for the peninsula plan as I have not finished final plan for it)

 

 

Enlarged peninsula (again, somewhat representative)

 

 

Slip switch location

Single or Double

The 2 tracks coming off the slip switch will be feeding the two container unloading/loading tracks located either side of that 'passenger station' in the original Tupper Lake plan.

 

The track on the left next to the aisle will be the 'escape track' for the locos that pulled the trains into the peninsula area to escape back to the freight yard area or the turntable,...a 22” radius one & a 24” radius one for bigger steamers.

Container crane (block of wood) straddling container tracks

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Posted by 7j43k on Saturday, December 08, 2018 1:10 PM

railandsail

Single or Double Slip Turnout

 

So here is my particular situation. I have two spur lines off of the mainlines feeding my peninsula area. It is desired that these 2 entering lines be able to select between either of 2 lines themselves. The most 'compact' manner to do such a thing is a slip switch.

A single slip switch accomplishes just what I want to do,...

Well, there's your answer.  In my opinion.  Railroads don't just use the double slip because it's cooler than a single.  If you are never going to use the "other" route, why allow for it?

...take the entering train and curve it around onto the same side, or cross it over to the other side. It does this in one single selection of the controller. It can remain on one single selection and do the same thing for trains entering from either track,...cross them over, or leave then curving around on the 'same track'.

Another nice feature of the single slip is that should the train stop, then get reversed while over this turnout, the train will NOT try to pick the opposite track and derail,,,as it might well do on a double slip switch. Is my thinking correct??

Since the double slip switch has 'another set of point rails' at its other end, that ARE NOT always set in the correct position, the train could well back up and try to chose a different route than it came in on. In other words it requires 2 control settings to get the dbl-slip to act in the manner I seek above, ….plus when I change the incoming route I have to make TWO selections to get it to operate like the single slip that I did not have to make any new selections.??

 

I am not following your reasoning here, on operation or control.  

However.  Since I advocate for the single slip, it then follows that you must be able to control it.  So, as they say:  "Do what it takes."  The same would be true of the double slip.

 

Ed

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Posted by railandsail on Saturday, December 08, 2018 2:35 PM

One other factor that might enter the equation, there are not many single slips sold, and I have only one that is a brass one. I have multiple numbers of double slips in NS

I am not following your reasoning here, on operation or control.
Ed

Did I not explain it correctly, or is there another question I have missed??

 

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Posted by 7j43k on Saturday, December 08, 2018 3:31 PM

railandsail

One other factor that might enter the equation, there are not many single slips sold, and I have only one that is a brass one. I have multiple numbers of double slips in NS

 

 

If you can't find an appropriate single slip, you are "stuck" with a double.  You could argue that the double was used instead of a single because your railroad had a FREE spare.  I can imagine that happening.

 

 
I am not following your reasoning here, on operation or control.
Ed

 

Did I not explain it correctly, or is there another question I have missed??

 

 

 

Perhaps you did explain it correctly.  I am just not following it.  But you already said that a single slip was appropriate, and I believe you.  So I don't need to follow the explaination of why.

 

Ed

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Posted by railandsail on Saturday, December 08, 2018 11:25 PM

Like a slip switch, but not a single or double slip

 

cx500

Perhaps I should also mention that as well as single slip and double slip turnouts, another related design was a diamond crossing with movable point frogs for the center pair.  These would be used where the crossing angle of two lines was very shallow, I'm guessing about 6 degrees or less.

 

This is one of the first mentions I've seen of such a turnout. I think I have such an animal I first referred to as a single slip. It says 'Atlas' on the back  #NS4547, Made in Austria,...likely a Roco.

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Posted by gmpullman on Sunday, December 09, 2018 12:28 AM
railandsail
This is one of the first mentions I've seen of such a turnout.

 

The movable point frog is only part of a turnout or crossing. In the example of a crossing there is no turnout at all (i.e. no choice of diverging routes) the design of such a frog is to reduce impact wear at the point of the frog itself.

 Frog_Sprung by Edmund, on Flickr

Some are sprung, others have actuating levers connected to an operating mechanism, either levers in a tower or remote motor drives,

 Frog_Sprung_drawing (2016_08_17 08_08_12 UTC) by Edmund, on Flickr

Here is an example of a single-slip on the New York Central main east of Collinwood Yard in Cleveland, Ohio at BR Tower, MP 171.

 CP171_BRtower by Edmund, on Flickr

 

Regards, Ed

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Posted by richhotrain on Sunday, December 09, 2018 9:26 AM

railandsail

Single or Double Slip Turnout

 

So here is my particular situation. I have two spur lines off of the mainlines feeding my peninsula area. It is desired that these 2 entering lines be able to select between either of 2 lines themselves. The most 'compact' manner to do such a thing is a slip switch.

A single slip switch accomplishes just what I want to do,...take the entering train and curve it around onto the same side, or cross it over to the other side. It does this in one single selection of the controller. It can remain on one single selection and do the same thing for trains entering from either track,...cross them over, or leave then curving around on the 'same track'.

Another nice feature of the single slip is that should the train stop, then get reversed while over this turnout, the train will NOT try to pick the opposite track and derail,,,as it might well do on a double slip switch. Is my thinking correct??

Since the double slip switch has 'another set of point rails' at its other end, that ARE NOT always set in the correct position, the train could well back up and try to chose a different route than it came in on. In other words it requires 2 control settings to get the dbl-slip to act in the manner I seek above, ….plus when I change the incoming route I have to make TWO selections to get it to operate like the single slip that I did not have to make any new selections.?? 

The double slip has four sets of point rails and two throwbars. So it typically requires two actions to set the route. The left side throwbar controls two sets of point rails that move in tandem. Likewise, the right side throwbar controls the other two sets of point rails that move in tandem. While this may sound problematic, it is not since the wheesets are only moving over one set of leftside points and one set of rightside points. 

With a single slip, there are only two sets of point rails, but there are still two throwbars. So, typically, it still requires two actions to set the route.

Rich

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Posted by railandsail on Sunday, December 09, 2018 9:53 AM

 A Case of Mistaken ID, ….Single Slip or What?
 

All of the slip-type turnouts I had in my possession were double slips by Peco and Roco. There was no doubts that these were dbl slips.
 

I had another slip turnout that I just assumed was a single slip as it had only one control motor. Now I am unsure if I identified it correctly?? Here is a photo of the two types together.

 

Then here is a photo of that mysterious turnout I first identified as a single slip. It is labeled an 'Atlas', made in Austria (likely by Roco), #4547. As I inspect it more closely it appears NOT to be a single-slip in our conventional thinking, but rather some 'automated crossover' ??


 

 

Here are a couple of other photos I found on the internet,...

 

Has anyone else experience with such a turnout?   ...and how would you name it??

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Posted by gmpullman on Sunday, December 09, 2018 10:07 AM

railandsail
...and how would you name it??

They are all double-slip switches.

Good Luck, Ed

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Posted by 7j43k on Sunday, December 09, 2018 10:34 AM

Here is a single slip switch by Roco:

 

 

Here is one by Peco:

 

 

Ed

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Posted by rrinker on Sunday, December 09, 2018 11:00 AM

 The ones Broan pictures are all double slips for sure. While there may be 4 sets of points in a double slip, there's no reason to use 4 switch motors, because some of the routes are conflicting. Really the only valid settings are for the two tracks to cross over, or to stay on the same side. Havine once unput crossing over and the other input staying straight makes no sense, even though it's possible to set it that way with multiple point motors. Looks like those pretty much just use 2 solenoids, to avoid crazy mechanical linkages to operate all the points from one. 

                                           --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by richhotrain on Sunday, December 09, 2018 11:01 AM

gmpullman
 
railandsail
...and how would you name it?? 

They are all double-slip switches.

Good Luck, Ed

I'll second that. Just count the point rails.

Rich

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Posted by richhotrain on Sunday, December 09, 2018 11:03 AM

rrinker

 The ones Broan pictures are all double slips for sure. While there may be 4 sets of points in a double slip, there's no reason to use 4 switch motors, because some of the routes are conflicting. Really the only valid settings are for the two tracks to cross over, or to stay on the same side. Havine once unput crossing over and the other input staying straight makes no sense, even though it's possible to set it that way with multiple point motors. Looks like those pretty much just use 2 solenoids, to avoid crazy mechanical linkages to operate all the points from one. 

                                           --Randy

 

Agreed. Double slips only need two switch motors, or two manual ground throws, or two flicks of the finger for Peco spring loaded points.

Rich

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Posted by richhotrain on Sunday, December 09, 2018 11:05 AM

7j43k

Here is a single slip switch by Roco:

 

 

Here is one by Peco:

 

 

Ed

 

Yep, only two pairs of point rails, thus a single slip switch.

Rich

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Posted by railandsail on Sunday, December 09, 2018 11:58 PM

If these two are BOTH double slip switches, why is the one on the right so much more complicated then the one on the left??
1) requires 2 switch motors rather than a single?

2) requires two operations to change from a simple crossing to a curved diversion

3) and requires a third input to change the crossing function from one side to the other.

The slip switch on the left with only a single switch machine in one position acts like a plain crossing to any trains entering it from either direction, and in the other position it acts like two side by side pieces of curved track. (the one on the right does NOT act in that same simple manner)


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Posted by gmpullman on Monday, December 10, 2018 12:14 AM

1: The switch motor on the left is designed to throw BOTH sets of points at the same time. Motor on the right only has the "mechanicals" at one end, thus two are required. The manufacturer chose this method so that a standard switch motor could be used rather than a special designed double-ended motor.

2: you are still doing "two operations" just that both are done by one motor (left) or two single-ended motors (right).

I use Shinohara double slips and have a Tortoise at each set of points. There are four combinations needed (Motor A: N or R and motor B N or R)

I use a rotary switch to choose my routes, very easy and straightforward. Everything here is lined for the main: (straight through)

 CP_Union_model_C by Edmund, on Flickr

 CP_Union_model by Edmund, on Flickr

 The LEDs tell me at a glance what my route is lined for.

 CP_Union_west by Edmund, on Flickr

Good Luck, Ed

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Posted by railandsail on Monday, December 10, 2018 9:37 AM

Ed
I use a rotary switch to choose my routes

Are rotary switches still readily available?

And I would need to figure out how to do such a 'control board' on a layout that plans on just using a wireless DCC (NCE) system for train control and PRIMARILY manual turnout controls.

 

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Posted by railandsail on Monday, December 10, 2018 9:39 AM

Ken

There’s more to the difference than that.  What you’re calling the US style ones have a single throwbar at each end to which all four points are physically attached.  That simplifies the mechanics.  What you’re calling the Euro ones have two throwbars at each end, each with two points attached, that move in opposite directions.

I strongly suspect the underlying reason for the difference is that in the four throwbar approach, if you don’t want the giant unprototypical blob next to the slip you’re going to have either a complex linkage under the roadbed, or four switch machines.  Where as with the two throwbar approach, you have a simple linkage under the roadbed with two switch machines.

Of course if you don’t mind the giant blobs next to your slips instead of scale switch machine linkage standins, then there is some advantage to the four throwbar approach given that you can control it with a single switch and have no possibility of a mis-set point on the far side.



Good point Ken, something I hadn't even considered. 

One must use that 'included' switch machine with this 'euro style' double slip, because that is where the different mechanical linkage is for the 'opposing throwbars'.

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Posted by NeO6874 on Monday, December 10, 2018 11:15 AM

railandsail

 

 
Ed
I use a rotary switch to choose my routes

 

Are rotary switches still readily available?

And I would need to figure out how to do such a 'control board' on a layout that plans on just using a wireless DCC (NCE) system for train control and PRIMARILY manual turnout controls.

 

 

 

Definitely - although technically you only need a toggle switch, same as any "regular" turnout, since you're only ever going to have "straight through" or "diverging".

 

That being said, the rotary switch would be a helpful indicator that "this isn't a normal turnout".

-Dan

Builder of Bowser steam! Railimages Site

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Posted by railandsail on Tuesday, December 11, 2018 8:56 AM

Which Type Double Slip to Use?

So here is my particular situation. I have two spur lines off of the mainlines (those 2 white curves at the top of the photos) feeding my peninsula area. It is desired that these 2 entering lines be able to select between either of 2 lines themselves. The most 'compact' manner to do such a thing is a slip switch.

 

 

 

We have now determined that I have 2 types of double slip turnouts,...one that is controlled by a single mechanism, and one that is controlled by two mechanisms. 

First Question:
Is there a preference for which style of double slip to use here? Does one have capabilities that the other does not??

Second Question: Switching routines
 (a subject I am not familiar with at all). Lets suppose a fairly long freight train attempts to enter the peninsula area on one of these two 'spurs' off the mainlines. Then it is desired to divide this consist up into groups of cars that might be taken to either of the 2 container tracks. or switched off that dbl-curve turnout (the one that follows the dbl-slip) into other portions of the peninsula complex.
I suspect some of this 'sorting of the cars' would involve the heavy use of this dbl-slip turnout that is in question, and the other incoming track as a temporary holding track? Plus the switching loco, that is pulling these groups of cars, needs some sort of way to get back around to the front of these deposited cars to pick up more singular or groups of cars??

Maybe I should ask this 'switching question' in its own separate subject thread??

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Posted by gmpullman on Tuesday, December 11, 2018 10:57 AM

NeO6874
Definitely - although technically you only need a toggle switch, same as any "regular" turnout, since you're only ever going to have "straight through" or "diverging".

Not quite...

I remember having an old, brass-rail AHM double slip. Maybe it was made by Roco or one of the other suppliers at the time. The way the points were arranged, all you needed to have, as you describe, was one toggle (momentary) and the route set for X or )( that was the only two choices. I think it even came with a lever-type actuating switch.

Now, on my third layout, I decided to use Shinohara code 83 track which, in the early 1990s, had a rather large inventory of switch configurations.

The double slips had confounded me at first since the "Entrance" and "Exit" points had to be aligned separately. So, you would need two toggles because each route required each Tortoise (or any other machine) to have four different arrangements, as I show A-B-C-D on my panel.

If you simply set the entrance points to normal but didn't set the exit points properly you would have a derailment. So instead of X or )( you could only choose   or  \  or  (  or  )  Each one required its own arrangement of the points.

Using DCC or Panel Pro I'm sure there are route-control macros that you can set up "Entrance - Exit" routes like some interlocking plants have. Again, for MY use, the rotary switches perform flawlessly and operators have a good grasp of selecting the correct routes.

Cheers, Ed

 

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