Double Slips

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D6130

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My German friend, who is a senior manager with DB, tells me that conventional double-slips are known colloquially as 'Englaender Weichen' or even just 'ein Englaender' amongst German railwaymen/women.

In the Italian speaking world (i.e. Italy, the Ticino canton of Switzerland and parts of Argentina) they are known as 'complessi inglesi'.

.....both of which would seem to indicate that they were invented and first used in this country.
 
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I'm all for progress and I'm a realist when it comes to maintenance etc but I hope you all agree the major pointwork at Newcastle and York is not nearly as fun to look at compared to what was there in the old days.
 

D6130

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I'm all for progress and I'm a realist when it comes to maintenance etc but I hope you all agree the major pointwork at Newcastle and York is not nearly as fun to look at compared to what was there in the old days.
True....but, IIRC, there are still three double slips at the East end of Newcastle station.
 

Watershed

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True....but, IIRC, there are still three double slips at the East end of Newcastle station.
Indeed there are, as well as a few at the west end. However that's a drastic reduction (to say the least!) on what was there before, and whilst there are some restrictions on simultaneous moves, the vast majority of the previous flexibility was kept whilst no doubt significantly reducing maintenance costs.
 

pompeyfan

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Both ladders at Waterloo and Clapham have several double slips, hence the 2017 derailment.
 

Sean Emmett

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Are double slips ever used in new trackwork? At one time they were widely used at the throats of goods yards as the start of the fan of sidings, simultaneously providing the entry to the headshunt in the opposite direction. They save space compared wiith sequential points.
Looks like Bristol Docks, near Brunel's Buttery (bacon butties etc) and the current mooring for the superyacht "Miss Conduct".
 

30907

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Locations such as Zurich Hauptbahnhof have whole ladders of double slips. I wonder how they manage maintenance?
Impressive, aren't they. On a much less congested site (massively rebuilt in the 50s IIRC and a couple of times since), with I suspect loads of redundancy built-in.
As a result each platform is less intensively used (a quick check suggests typically 1 offpeak departure per hour from each terminus platform).
 

Big Jumby 74

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Then there are "Barry slips" - think there's still one in Woking Down Yard.
I never knew there was a name for them, thank you. I guess you are referring to this one under 66.564? Its still there and used most days for the aggregate trains. As mentioned up thread Waterloo West Crossings has a number, I believe it's 4 x double slips and 3 x singles, then there are one of each between West Crossings and the platform ends on the Windsor side, and, probably the most heavily used were (pre covid at least) the double slip at the entrance/exit of platforms 8/9 and the same again outside platforms 12/13. Back then these two were an operational necessity for the level of train service using the station, and given the cramped location will always need bespoke components to keep them going.
 

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Bald Rick

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Locations such as Zurich Hauptbahnhof have whole ladders of double slips. I wonder how they manage maintenance?

well I bet they are swung rather less; some of the double slips at Liv St are swung several hundred times a day. I think we once recorded one set swinging on average once every 90 seconds.

and those at Liverpool st have awkward curved geometry, whereas those at Zurich will all be in straight track, which makes the forces on the switch blades somewhat lower.

finally the Liverpool St slips are all in critical parts of the layout - to maintain them you have to take out platforms 5-10 minimum, and some types of work (and most failures) take out 1-10. Zurich has plenty of redundancy.
 

furnessvale

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well I bet they are swung rather less; some of the double slips at Liv St are swung several hundred times a day. I think we once recorded one set swinging on average once every 90 seconds.

and those at Liverpool st have awkward curved geometry, whereas those at Zurich will all be in straight track, which makes the forces on the switch blades somewhat lower.

finally the Liverpool St slips are all in critical parts of the layout - to maintain them you have to take out platforms 5-10 minimum, and some types of work (and most failures) take out 1-10. Zurich has plenty of redundancy.
Thanks for that.

Just a bit of lateral thinking. Would the installation of MORE double slips actually increase redundancy, reducing the load on any given set of points and provide alternative routes when things do go wrong?
 

zwk500

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Thanks for that.

Just a bit of lateral thinking. Would the installation of MORE double slips actually increase redundancy, reducing the load on any given set of points and provide alternative routes when things do go wrong?
That would depend on whether the signalling system would be set up to balance the load over alternative routes or if it had ranked preferences. It also of limited help in a maintenance situation if running trains would still be too close to the working staff.
 

Big Jumby 74

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One for 'Western Sunset' if I may. Are you able to comment as to the origins of the phrase 'Barry Slip' by chance? Just curious, that's all. There was also one in number 1 Siding at Wimbledon West Yard, alongside the Down Wimbledon Chase line, as it once was. Cheers.
 

mr_moo

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They are very much 'non-preferred' S&C arrangements but they are definately still used in places where there are particular constraints.

Not passenger, but Acton yard remodelling (as part of the Acton diveunder construction) used them given the space constraints:
https://goo.gl/maps/HNH6j34Zq2Ld9xEc9 and
https://goo.gl/maps/HBRutBsUzKNDiYSR8

Gidea Park (remodelled as part of the Crossrail project) installed them, again as the only way to fit the required siding lengths in. Whilst not normally passenger, it is technically authorised for passenger traffic.
https://goo.gl/maps/2DFrfU11QNDKnoFU7 and
https://goo.gl/maps/nfUsJwJVfaKT6ySf7

From the current NR track design standard:
1646323321935.png

Also, a few years back now, several types of slips were withdrawn from the standard list of available S&C types, to reduce the number being used and introduce more standardisation, and all remaining ones are listed as 'non-preferred' types of S&C.

So essentially, yes they can be used, and still are in places. They are restricted to 40mph max (60mph by exception and where cast crossings are used), are non-preferred, and remain a maintenance headache to the poor sods who get given them as installed assets once projects have finished, but they are useful and do save space, so are still on the options list where space is tight.
 
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mr_moo

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Your Reading example looks like a scissors crossing, not a slip.
You are right - Oops! I had in my memory they were slips and found the links without actually considering what my eyes were telling me. I feel foolish now!

I'll edit the post to remove the Reading ones! Thanks. :)
 

Big Jumby 74

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Your Reading example looks like a scissors crossing, not a slip.
I concur with that. This arrangement, prior to the 2017 rebuild at Waterloo, was the pattern immediately outside platforms 1/2, and also outside 3/4 (and similarly on the Windsor side) which given the 8 car railway in operation at the time, was in my humble opinion, the optimum arrangement for maximising the use of platforms 1-4.

You are right - Oops!
My apologies, was still typing and didn't see your subsequent post !
 

LSWR Cavalier

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Or even more simply as DKW-500-1:9 (or EKW as the case may be), with the 500 giving the radius and the 1:9 the crossing-angle. They were introduced in 1935 as one of the DR standard designs. "Normal" slips were of a 190-metre radius.
Modell Eisenbahner (12/2021) had an article about the DB Weichen Werk Witten with a nice photo of a DKW 54-190 1:9. 'WWW' makes parts for high-speed turnouts, the rails are heated up to 900°.

More vocab: the thing we call a frog, they call a Herzstuck, heart piece.
 

norbitonflyer

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Worth noting that in the German speaking world, a doppelte Kreuzungsweiche is usually shortened to DKW
DKW was also the name of a German vehicle manufacturer. The initials originally stood for Dampf-Kraft-Wagen (steam powered car) but within three years of its founding during World War I, it had switched to internal combustion and repurposed the initials variously as Des-Knaben-Wunsch, "the boy's wish (for working models) "Das-Kleine-Wunder", "the little wonder" (motorbikes) or "Deutsche Kinder-Wagen" - "German kids' car". ". Various mergers eventually saw it become part of Audi.
 

mr_moo

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What an awesome picture! Any idea what date that's from? It both makes my head hurt and also I'm in awe. :)
 
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