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.
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).
A double-slip is effectively options 1 and 3 or options 2 and 4 laid over each other.
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.
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
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.
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
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.
Here is a closeup of one of the Peco Code 83 double slip switches.
These are spring loaded switches that I operate with a flip of the finger against the point rails.
Rich
Thanks Rich
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)
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?
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
Did I not explain it correctly, or is there another question I have missed??
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.
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
Like a slip switch, but not a single or double slip
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.
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.
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 C
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 problema
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,…
They are all double-slip switches.
Good Luck, Ed
Here is a single slip switch by Roco:
Here is one by Peco:
Ed
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