Mechanical Doubleslips

[Compound2632]

I am struggling, with the aid of diagrams, to understand how a double slip with all four pairs of switch blades operated by a single lever can provide all four possible routes. 

[TheSignalEngineer]

Possibly, I remember it being near to the footbridge where that was taken.

[Grovenor]

11 hours ago, Compound2632 said:

I am struggling, with the aid of diagrams, to understand how a double slip with all four pairs of switch blades operated by a single lever can provide all four possible routes. 

It changes from a diamond crossing where either crossing route can be used to a bit of interlaced track where either slip road can be used. The pairs of blades at each end work in opposition not together as in the usual arrangement.

Rgds

[Keithnewton]

Came across this topic after searching for information regarding point rodding and cranks for double slips.

My example is where each end of the DS is controlled by a lever in the signal box. - I have assumed that each stretcherbar is connected to an adjusting crank and these would move together (one end of DS) - however the two cranks operating rods would have to connect together somewhere in order to connect to the next crank and eventually to the signal box lever, see diagram

Does anyone have any drawings or photos how this was done please?

 

Edited February 16, 2020 by Keithnewton
spelling mistake

[TheSignalEngineer]

Close to the adjusting cranks one of these is used underneath the channel rodding to split off the second drive.

https://portal.unipartrail.com/Catalogue/ViewProduct.aspx?sku=1815&Dept_ID=1170&CatNumber=0086/063201

[Keithnewton]

Thank you for your reply

 

I guess the "channel" is for the main rod to go though and the second rod is connected to the lug?

Do you know how this is mounted, ie is the "lug"  at the top, bottom or side? as below:

 

[Compound2632]

3 hours ago, Grovenor said:

It changes from a diamond crossing where either crossing route can be used to a bit of interlaced track where either slip road can be used. The pairs of blades at each end work in opposition not together as in the usual arrangement.

Rgds

 

Thanks, that makes sense now. A multiplicity of cranks there - must have needed some heft to get the lever over - and not something that can be replicated using any of the Peco double slips!

[The Stationmaster]

22 hours ago, Keithnewton said:

Thank you for your reply

 

I guess the "channel" is for the main rod to go though and the second rod is connected to the lug?

Do you know how this is mounted, ie is the "lug"  at the top, bottom or side? as below:

 

As it is channel rodding the lug will be at the bottom because the channel is the under part of the rod in order to lie on the rollers. As can be seen more or less dead centre in this view (click on the image to enlarge) -

 

[Gordon A]

Something in the back of my mind thinks that double slips in the main running line on the Western had a speed limit imposed on the trains passing over them ie 15mph?

 

Gordon A

[The Stationmaster]

3 hours ago, Gordon A said:

Something in the back of my mind thinks that double slips in the main running line on the Western had a speed limit imposed on the trains passing over them ie 15mph?

 

Gordon A

I doubt it as there was one in the Up Main at Patney & Chirton and I can't really see the Up 'Limited' dropping down to 15 mph to run through on the 'straight' road.  But almost certainly 15 mph (or less) through the divergences.

[MidlandRed]

On 13/02/2020 at 02:26, Swindon 123 said:

Allscott signal box between Shrewsbury and Wellington (Salop) has a double slip, and on a 70MPH main line as well. It was operated by rodding. See picture below on my Flickr site of said location after the box had shut. 

 

 

Paul J.

 

Clearly not here either - 70 mph on the through roads. The slip looks a tight turn though (possibly foreshortened in the photo).

[Keithnewton]

On 17/02/2020 at 12:11, The Stationmaster said:

As it is channel rodding the lug will be at the bottom because the channel is the under part of the rod in order to lie on the rollers. As can be seen more or less dead centre in this view (click on the image to enlarge) -

 

Thanks Mike

Good picture and example of how it works for channel rodding. 

Is it the same / similar for pre grouping round rodding?

[TheSignalEngineer]

On 17/02/2020 at 13:04, Gordon A said:

Something in the back of my mind thinks that double slips in the main running line on the Western had a speed limit imposed on the trains passing over them ie 15mph?

 

Gordon A

The turnout side was, as with crosovers, limited to 10mph unless otherwise stated according to the WTT.

[The Stationmaster]

21 hours ago, Keithnewton said:

Thanks Mike

Good picture and example of how it works for channel rodding. 

Is it the same / similar for pre grouping round rodding?

Definitely was normally the case on the Western (Great and Region) and no doubt the same elsewhere because the drive from the lug would be going to a crank. set below the level of the rodding run.  You might possibly find examples of something different used in specialised circumstances but I've never seen, or photographed, any (which obviously doesn't mean they didn't exist!).