Western region K crossing vs double slips.

[Simon Moore]

Tonight at the club we've been discussing double slips & I was told that the gwr had k crossings.

 

After a glimpse in Iain Rices book I was show the k crossing. Was this something that was used instead of double slips in every case or was the double slip something still used because a no one could come up with answer properly.

[micknich2003]

A "K Crossing" and a Double Slip, are two completely different things.

[micknich2003]

A "K Crossing" and a Double Slip, are two completely different things.

[martin_wynne]

Tonight at the club we've been discussing double slips & I was told that the gwr had k crossings.

 

Hi Simon,

 

A diamond-crossing formation comprises 2 V-crossings and 2 K-crossings, like this:

On the GWR and BR(W), K-crossings were usually called "elbow crossings".

 

On many railways, V-crossings are often called "common crossings", and outside the UK they are often called "frogs". And K-crossings are sometimes called "obtuse crossings".

 

As you can see, the terminology varies a lot with different railway companies and time periods.

 

A diamond-crossing can be converted to a slip by adding 1 or 2 slip roads, which allow trains to move from one road to the other. Doing that doesn't affect the K-crossings and V-crossings. On the GWR and BR(W) a slip was often called a "compound".

 

Here is a screenshot from a Templot video explaining about slip roads. Templot is a computer program which allows modellers to design track formations like these (and complete track plans):

 

 

 

The video is available in several formats here: http://templot.com/companion/index.html?add_slip_roads.htm

 

regards,

 

Martin.

Edited September 23, 2015 by martin_wynne

[BR60103]

Note in the diagram that the rails of the slip road may interfere with the guard rails of the K crossing.

[martin_wynne]

Note in the diagram that the rails of the slip road may interfere with the guard rails of the K crossing.

 

Yes, that's covered in the video: http://templot.com/companion/index.html?add_slip_roads.htm

 

 

Martin.

Edited September 23, 2015 by martin_wynne

[Joseph_Pestell]

I think that there is some confusion here.

 

What (I think) OP is talking about is an arrangement of two turnouts plus a diamond giving a sort of outside single slip. I can recall CJ Freezer referring to this as a K crossing (on a rare plan for continental modelling).

 

So, in answer to that, it is an arrangement that could be found on all railways and not, I think, any more common on the GWR than elsewhere. It gives the same result as an inside single slip but may enable a higher running speed depending on crossing angles etc.

[Trevellan]

Bilton Junction K Switches.jpg

I've heard these called "switched diamonds". As others have said, it allows higher running speeds because the gap in an ordinary diamond is closed.

[stadman]

I'd never heard of K crossing s until I joined RM Web.

What they really mean is Obtuse Crossing. Frog is only a modellers term for common crossing as it's common to switches (Points) and crossings. Pictured above as already noted is a "Switch Diamond"

[Grovenor]

I think that there is some confusion here.

 

What (I think) OP is talking about is an arrangement of two turnouts plus a diamond giving a sort of outside single slip.

I see nothing in the OPs post to suggest he was thinking of an outside slip. Micknich clearly thought he was thinking of a switched diamond! Perhaps the Op could come back and enlighten us.

 

I can recall CJ Freezer referring to this as a K crossing (on a rare plan for continental modelling).

Well, maybe he did, but I have only heard of a K crossing as synonymous with obtuse crossing as others have said above. Regardless of whether a slip is inside or outside it still has 2 K crossings.

 

A switched diamond can easily be mistaken for an alternative to a double slip if it is not realised that the two sets of switches work in opposition.

Regards

[martin_wynne]

I'd never heard of K crossing s until I joined RM Web. What they really mean is Obtuse Crossing. Frog is only a modellers term

 

What folks really mean is usually what they say. "K-crossing" is a long-standing permanent-way term. Here is a scan from the NER drawings book of 1912. "Frog" is the standard permanent-way term for a common crossing in America and elsewhere, and is becoming used in the UK in reference to cast crossings.

 

 

Martin.

[martin_wynne]

What (I think) OP is talking about is an arrangement of two turnouts plus a diamond giving a sort of outside single slip. I can recall CJ Freezer referring to this as a K crossing

 

Hi Joseph,

 

That's usually called a "half-scissors". Here is a curved one at Shrewsbury in 1978:

 

 

Martin.

[Simon Moore]

Wow

 

Very detailed answers here. Am I right in thinking then that the k crossing or obtuse crossing is different to a double slip & a double slip would still have been used by the gwr / br western region.

 

I was told these were used instead of double slips, I struggled to believe this as I thought track standards were the same for all railway company's.

[Grovenor]

Wow

 

Very detailed answers here. Am I right in thinking then that the k crossing or obtuse crossing is different to a double slip & a double slip would still have been used by the gwr / br western region.

Simon,

Refer back to post #4. Each diamond, single slip or double slip has two K (=obtuse) crossings as part of it. A double slip is a complete formation, a K crossing is just a component. The only difference on the GWR is nomenclature, they called double slips "double compounds", and they called 'K crossings' 'elbow points'.

 

I was told these were used instead of double slips, I struggled to believe this as I thought track standards were the same for all railway company's.

Some one was confused but we still don't know what your 'somebody' meant by a K crossing, was it that illustrated in post #3 or post #12 or ?????

 

For some info on GWR track you can look through http://www.norgrove.me.uk/permanent_way_notes.htm

Regards

Edited September 23, 2015 by Grovenor

[Joseph_Pestell]

Hi Joseph,

 

That's usually called a "half-scissors". Here is a curved one at Shrewsbury in 1978:

 

 

Martin.

 

Nice photo.

 

That was what I thought the OP was talking about. I would not have called it a K crossing but it seemed that his colleagues were. How anyone might confuse a switched diamond with a K-crossing (fixed diamond) with a slip is quite beyond me.

[Southernman46]

Bilton Junction K Switches.jpg

Yes 'cos nobody'd EVER use a set of switch diamonds to cross a tamper from line to line - would they ? ...... 

 

 

The common-obtuse-common combination in a scissors layout these days come as a 3-part cast manganese unit referred to as a "saddle" crossing

Edited September 23, 2015 by Southernman46

[Grovenor]

 

 

That was what I thought the OP was talking about. I would not have called it a K crossing but it seemed that his colleagues were. How anyone might confuse a switched diamond with a K-crossing (fixed diamond) with a slip is quite beyond me.

As you said before, but the OP was specific about substituting a K crossing for a "Double slip", not a single slip.  And, unfortunately the OP's second message did not add any clarification.

And the friend was talking about the GWR and hence should have been talking elbow points or movable elbows.

 

 

 

Yes 'cos nobody'd EVER use a set of switch diamonds to cross a tamper from line to line - would they ? 

One of the problems caused by using two separate point machines for switch diamonds, no direct linkage so they can be clipped and scotched the wrong way.

I've seen it done (a long time ago) with a real train, never mind a tamper.

Regards

[phil-b259]

 

One of the problems caused by using two separate point machines for switch diamonds, no direct linkage so they can be clipped and scotched the wrong way.

I've seen it done (a long time ago) with a real train, never mind a tamper.

Regards

 

If clamp locks (hydrarlic points) are employed, a  single pump unit can drive all 4 rams (2 rams per end) together both sets of switch rails will move at the same time  and in the correct direction (It doesn't matter weather you are hand pumping or moving them under power).

[phil-b259]

Tonight at the club we've been discussing double slips & I was told that the gwr had k crossings.

 

After a glimpse in Iain Rices book I was show the k crossing. Was this something that was used instead of double slips in every case or was the double slip something still used because a no one could come up with answer properly.

 

In discussions about points it is important to distinguish between the individual parts, i.e. switch rails, stock rails, common crossing, V crossing, K crossing, etc and the overall function of the arrangement of the rails.

 

The term single slip, double slip, turnout, fixed diamond switch diamond, etc all refer to a arrangement of discrete components - most of which can be renewed / repaired on an individual basis.

 

A turnout will consist of at least 2 sets of switch rails & stock rails, and at least one crossing unit - the type depending on the geometry of the installation and the rail profile being used.

 

The terms "diamond crossing" and "frog" are not used on the real thing despite their widespread use in the model world, the former being a mixture of two completely separate things.

 

It would appear that in the course of your discussions at the club some significant confusion has crept into the conversation which has led to you asking a question linking two things that belong to totally different categories as it were. This is understandable as unless you have experience of the real thing and deal with p-way then it can be hard to get to grips with all the terminology used.

Edited September 23, 2015 by phil-b259

[Grovenor]

 

 

The common-obtuse-common combination in a scissors layout these days come as a 3-part cast manganese unit referred to as a "saddle" crossing 

This is getting well away from the OP's question, but these cast crossings may be in 3 parts, in which case there are two common crossings and a saddle crossing between them, or in one single part known as a 'combined saddle crossing'.

 

 

 

The terms "diamond crossing" and "frog" are not used on the real thing despite their widespread use in the model world, the former being a mixture of two completely separate things.

The formation where one track crosses the other is usually referred to just as a "diamond". Frog however is used on the real thing, unless you don't consider the USA to be real.

Regards

[micknich2003]

 The attached five pictures may be of interest. A "Modern" Double Slip with K Crossings/Switch Diamonds, Hull Paragon.

[mightbe]

^ There aren't any K-crossings in the above pictures. Those are all switched diamonds, which were required on any diamond broader than 1:8 for safety reasons. Slips of 1:8 or tighter could have K crossings, though I imagine some 1:8 slips would've had switched crossings installed, particularly any slips on running lines (trailing slips I imagine). It's important to remember that you can only have one or the other. K crossings are fully fixed formations. Switched diamonds include two sets of points which are very bluntly angled relative those used on turnouts.

 

K crossings/obtuse crossings/elbow crossings are fundamentally different from switched crossings, and the two mustn't be confused or thought of as interchangeable. Likewise, a slip or a diamond may use either (a slip is still a slip regardless etc), provided the angle is sharper than 1:8. If broader, a switched diamond must be used instead.

 

Now, it's a bit silly to say that the GWR had no crossings (either in slips or as plain diamonds) broader than 1:8. Obviously they had much larger diamonds on the network, and they would have used switched diamonds.

 

I'm going to speculate that your friend's terminology was so badly jumbled that you'd have to ask him again to derive any real meaning from the point he was trying to make.

 

Quentin

Edited September 28, 2015 by mightbe

[The Stationmaster]

 

Now, it's a bit silly to say that the GWR had no crossings (either in slips or as plain diamonds) broader than 1:8. Obviously they had much larger diamonds on the network, and they would have used switched diamonds.

 

 

 

Quentin

They did - but they didn't have very many (and was it 1 in 8 for a switched diamond back then or was it a little broader - I only ask that in view of the fact that such diamonds were so few in number across the GWR network although obviously speeds were lower). 

[micknich2003]

The NERly and the LNER called them "K Crossings", and so did the railwaymen I worked with, see attached NERly drawing of 1912.

 

[martin_wynne]

They did - but they didn't have very many (and was it 1 in 8 for a switched diamond back then or was it a little broader - I only ask that in view of the fact that such diamonds were so few in number across the GWR network although obviously speeds were lower). 

 

Hi Mike,

 

The GWR and BR(W) term for switch-diamonds was "Movable Elbows".

 

The limit for "Standard Diamonds" with fixed elbows (Fixed K-Crossings) was 1:8 in straight track, and shorter in curved track:

 

In radius down to:   the flattest angle for a fixed K-crossing is:

60 chains ( 3960ft )........1:8

30 chains ( 1980ft )........1:7.75

20 chains ( 1320ft )........1:7.5

15 chains ( 990ft ).........1:7.25

12 chains ( 792ft ).........1:7

10 chains ( 660ft ).........1:6.5

below 10 chains.............1:6

 

The above information is dated 1943 for the GWR.

 

Quentin wrote:

There aren't any K-crossings in the above pictures.

 

Switch-diamonds have "Movable K-Crossings", so described by several companies (and in Templot).

 

regards,

 

Martin.