Single & double slips

 
  Groover Train Controller

Location: A long way from home
I'm looking at using a double slip on my layout as a space saver.  It would be on a main line at a station that has express trains passing.  In real life would slips be used on the mainline?  I have seen them in station yards eg. Hornsby but do their engineering complexity preclude express traffic passing over them at speed on the straight section, e.g. XPT or Southern Aurora.

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  x31 Chief Commissioner

Location: gallifrey
What is a double slip?
  Groover Train Controller

Location: A long way from home
What is a double slip?
x31
https://www.peco-uk.com/product.asp?strParents=3309,3322&CAT_ID=3327&P_ID=17438
  x31 Chief Commissioner

Location: gallifrey
Thankyou for the link.

What then is a single slip?
  awsgc24 Minister for Railways

Location: Sydney
I'm looking at using a double slip on my layout as a space saver.  It would be on a main line at a station that has express trains passing.  In real life would slips be used on the mainline?  I have seen them in station yards eg. Hornsby but do their engineering complexity preclude express traffic passing over them at speed on the straight section, e.g. XPT or Southern Aurora.
Groover
Hornsby had double and single slips on the main lines, until resignalling in about 2000 when some of them were deleted.

The remainder of double and single slips on both main lines and sidings were deleted with recent remodelling. There is one ordinary diamond for the Shore Turnback. Hornsby also has Scissors Crossovers.

At Erskineville, a single slip still exists when going from Depot to the Illawarra Main lines.

Victoria used to have quite a lot of slips; NSW tended to avoid them. Where were they.

One advantage of slips over a ladder of plain turnouts that might replace them, has to do with mechanical operation of the points.
* slips can be closer to its signal box, which causes less stiffness of the points.
* The new layout at Hornsby could not be worked by a mechanical signal box.
* slips need less point detection, which is less of a problem with electric operation.
  apw5910 Deputy Commissioner

Location: Location: Location.
Thankyou for the link.

What then is a single slip?
x31
Like a double slip but only one side is a turnout, the other side is a plain diamond crossing. See

https://dccwiki.com/File:CrossingSingleSlip.gif

from https://dccwiki.com/Crossing
  Groover Train Controller

Location: A long way from home
Thankyou for the link.

What then is a single slip?
x31
Single slip:
https://www.peco-uk.com/imageselector/Files/Track-templates/SL-80.pdf

Double slip:
https://www.peco-uk.com/imageselector/Files/Track-templates/SL-90.pdf

The following link describes outside slips of which I think there was one at Junee and now in Dorrigo museum?  I think I read that somewhere on RP.
https://en.wikipedia.org/wiki/Railroad_switch

It seems to me that European railways use more complicated trackwork than in Aus and they don't mind entering it at high speeds.  That's my observation.  I was going to try and make a HO scissors crossing with one turnout replaced by a double slip as the ultimate space saver.  It would mean cutting and splicing but expensive especially if the rollingstock don't like it!  There are examples on Youtube of folks in the UK doing it.  You can do it with set pieces however the track spacing is huge.
  apw5910 Deputy Commissioner

Location: Location: Location.
I was going to try and make a HO scissors crossing with one turnout replaced by a double slip as the ultimate space saver.  It would mean cutting and splicing but expensive especially if the rollingstock don't like it!  There are examples on Youtube of folks in the UK doing it.  You can do it with set pieces however the track spacing is huge.
Groover
Or get some rail and cut some printed circuit board sleepers and bang out your own for peanuts. It really isn't hard, and you can make any track pattern you need.

There was a very good series of articles in AMRM many years ago (by Clive Huggan? Just called "Track" I think) which showed how to do it. There's probably a zillion websites/youtubes by now.
  DJPeters Deputy Commissioner

In South Australia there was numerable double slips on mainlines but nearly all had permanent speed restrictions over them though as facing points even on a double slip were not really trusted by the look of it. My Local station at Kilkenny had had a double and a single slip on the same track years ago before it all got ripped out. But you have to remember though that trains back then went a bit slower than modern trains do, they were not known to be that speedy really. The line this is on though only had suburban trains and goods trains work on it no top notch express trains though, although the Overland has passed through Kilkenny on more than one occasion in the past both with and without passengers on board. The Overland was sometimes run down around the loop at Outer Harbor to turn the whole consist around, presumably to even out the wear on the wheels. One of the last runs it made it ran direct from Melbourne to Outer Harbor and then back to Adelaide to drop off some passengers that missed a cruise boat that left Melbourne with out them being back on board and so they were all put onto the Overland and did the run as above via the Gaol loop. They rejoined the cruise at Outer Harbor, and the Overland ran back to Adelaide!

The old Adelaide yard had just about everything in the way of track pieces as you could enter or leave any platform from anywhere and double slips abounded to save space. All have since been removed though in the rebuild here!

I think modern set up's try to use as much standard track pieces like points as much as they can and so do away with double slips and things like that. The new entry to Adelaide Yard from the Gawler line to the Outer Harbor line is all done in simple crossovers using standard points to do it. The old track was nearly all double slips at one time here till recently when the new track dive and track rearrangement happened.
  awsgc24 Minister for Railways

Location: Sydney
A plain diamond can have a crossing angle, AFAIK, of about 1 in 15, before wheels risk going the wrong way at the "K-Crossings". If 1 in 15 is too fine an angle, then "switched diamonds" can be used to replace the K-crossings. UK has lots of switched diamonds.

Plain diamonds can be 90 degrees.

Slip diamonds are limited to crossing angles (in NSW) of about 1 in 7.5 to 1 in 8.25, since a coarser angle would require too sharp curves.

Trains magazine in a recent article had an article called "Diamonds are not a Railroad's best friends." Crossings let alone slips cause high maintenance costs and speed limits. If there is room to replace slips and diamonds with ladders of plain turnouts, maintenance costs are minimised, and high speeds are possible. Chicago has lots of 90 degree crossings.

FYI, turnouts have one "V-crossing."
FYI, slips and crossings have two V-crossings and two K-crossings.
  Groover Train Controller

Location: A long way from home
In South Australia there was numerable double slips on mainlines but nearly all had permanent speed restrictions over them though as facing points even on a double slip were not really trusted by the look of it. My Local station at Kilkenny had had a double and a single slip on the same track years ago before it all got ripped out. But you have to remember though that trains back then went a bit slower than modern trains do, they were not known to be that speedy really. The line this is on though only had suburban trains and goods trains work on it no top notch express trains though, although the Overland has passed through Kilkenny on more than one occasion in the past both with and without passengers on board. The Overland was sometimes run down around the loop at Outer Harbor to turn the whole consist around, presumably to even out the wear on the wheels. One of the last runs it made it ran direct from Melbourne to Outer Harbor and then back to Adelaide to drop off some passengers that missed a cruise boat that left Melbourne with out them being back on board and so they were all put onto the Overland and did the run as above via the Gaol loop. They rejoined the cruise at Outer Harbor, and the Overland ran back to Adelaide!

The old Adelaide yard had just about everything in the way of track pieces as you could enter or leave any platform from anywhere and double slips abounded to save space. All have since been removed though in the rebuild here!

I think modern set up's try to use as much standard track pieces like points as much as they can and so do away with double slips and things like that. The new entry to Adelaide Yard from the Gawler line to the Outer Harbor line is all done in simple crossovers using standard points to do it. The old track was nearly all double slips at one time here till recently when the new track dive and track rearrangement happened.
DJPeters
I think that answers my question.  Thanks.
  The railway dog Junior Train Controller

Location: Adelaide Hills
Groover
You mention NSW in your first post so I'll go with that.
From observation, I don't think the old NSWGR liked slips much. They save linear space at the cost of complexity, & NSW tended not to be short of linear space. They only seem to've been used in busy yards where space mattered.
No doubt those more knowledgeable than I could post examples of them in obscure places.
  Groover Train Controller

Location: A long way from home
Groover
You mention NSW in your first post so I'll go with that.
From observation, I don't think the old NSWGR liked slips much. They save linear space at the cost of complexity, & NSW tended not to be short of linear space. They only seem to've been used in busy yards where space mattered.
No doubt those more knowledgeable than I could post examples of them in obscure places.
The railway dog
Thanks for your comments.  I was watching a video on youtube from the cab of a "high speed" train train between Venice and Verona and they take the through road in slips at non-stopping station yards at some speed.  So to hedge all my bets I'm going to build the station with the slip on the main and see what happens. If some locos and rolling stock have probs I'll go to a simple ladder and place the slip in the fiddle yard.  I bought the Peco Code 100 d/slip some years ago.  My other solution was to go with all new Code 83 Tillig or Roco track on the mains and put the Peco stuff in the storage areas.  I'm baulking at the cost of that experiment!
  catchpoint Assistant Commissioner

Location: At the end of a loop
Groover
You mention NSW in your first post so I'll go with that.
From observation, I don't think the old NSWGR liked slips much. They save linear space at the cost of complexity, & NSW tended not to be short of linear space. They only seem to've been used in busy yards where space mattered.
No doubt those more knowledgeable than I could post examples of them in obscure places.
The railway dog


Rydalmere on the Carlingford branch - pre it being rationalised, had a slip in the goods yard, one half was connected to the interlocking - Frame 'B' for access off the main to the slip, the other half was operated by ball type levers.

Rydalmere was quite a space constrained location between Victoria Road (level crossing pre-overbridge) at the down END and Vineyard Creek at the UP end.

Regards,

Catchpoint
  sol Assistant Commissioner

Location: Evanston Gardens SA
I have single & double slips and they give no problems & I just tested a Peco single slip  with a mix of bogie & 4 wheelers both forward & backward at speed thru the curved section and was pleased to see no derailments. And if there were problems then it would be the wagons so they would get checked for back to back, etc & weight.
  The railway dog Junior Train Controller

Location: Adelaide Hills
Groover
Best wishes for the choice you eventually make. You wouldn't be the first NSW modeller to put a slip on a main line I'm sure.

Catchpoint
I well remember looking down on Carlingford station from the bridge in days gone by, thinking what a nice layout it'd make. A NSW version of those  English branch termini.

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