Unusual PW configurations thread both real and model.

[jim.snowdon]

And rather like track itself, only two rails until you get to the complicated bits, aka switches and crossings.

 

Jim

[Budgie]

Here's an interesting photo of Swindon in the broad-gauge era.

 

 

I love that mixed-gauge outside single slip in the left foreground, especially that frog where all three directions pass through it.

[RRU]

Here's an interesting photo of Swindon in the broad-gauge era.

 

Swindon track1.jpg

 

I love that mixed-gauge outside single slip in the left foreground, especially that frog where all three directions pass through it.

That would be a challenge for Hayfield on his turnout workbench!

 

Peter

[PatB]

Here's an interesting photo of Swindon in the broad-gauge era.

 

Swindon track1.jpg

 

I love that mixed-gauge outside single slip in the left foreground, especially that frog where all three directions pass through it.

And the way the slip road swaps "sides" on the way through .

[jim.snowdon]

Here's an interesting photo of Swindon in the broad-gauge era.

 

 

 

I love that mixed-gauge outside single slip in the left foreground, especially that frog where all three directions pass through it.

  Crossing, please. "Frogs" in pointwork are best left with the Americans. 

[Budgie]

  Crossing, please. "Frogs" in pointwork are best left with the Americans.

Whatever you call it, I'd like to see a diagram of it.

[jim.snowdon]

Whatever you call it, I'd like to see a diagram of it.

Your wish is my command...

 

 

To help with reading it, I have thickened up the gauge face of the rail and drawn in where the check rail would be if it was fitted - from the picture there doesn't appear to be one on this crossing, although the opposite obtuse crossing is fitted with one. The hatched area is not traversed by the wheels on any route - akin to a wing rail.

 

Jim

[Budgie]

This looks like the rails will not support the wheel treads throughout the crossing, so I assume some running on the flanges would be necessary. Even though it's only a short distance I would have thought that the forces involved in that would be rather high and liable to cause the crossing to wear out rather quickly unless some form of lubrication was used.

[martin_wynne]

Whatever you call it, I'd like to see a diagram of it.

 

There was an article on building one of these 3-way K-crossings in "Scalefour News" no. 178, July 2012, by Michael Godfrey (journal of the Scalefour Society).

 

 

The article contains some very detailed notes and close-up photos of such crossings, but I can't post them here because of NRM copyright. The article is available on the web site (members only) at: http://www.scalefour.org/members/newsarchive/dl.php?f=s4news178.pdf

 

Martin.

Edited February 27, 2016 by martin_wynne

[jim.snowdon]

This looks like the rails will not support the wheel treads throughout the crossing, so I assume some running on the flanges would be necessary. Even though it's only a short distance I would have thought that the forces involved in that would be rather high and liable to cause the crossing to wear out rather quickly unless some form of lubrication was used.

Correct, Flange running does not seem to have been unusual in mixed gauge track, particularly the fixed switches that were used whenever the common rail changed sides.

 

However, beyond the GWR's mixed gauge track, flange tip running through crossings is very much the preserve of street tramways, where the narrower wheels make it a necessity if wheel drop is not to occur through crossings. In the modern age, ie post WW2, most tramway flanges are flat at the tip, which will help with distributing the stresses, but British tramways got along quite happily with round flange tips and flange running crossings for the best part of a century. It only stopped being used in the traditional manner when the UK got rid of all bar one of its tramways. Modern British tramways follow European practice, with the wider wheels treads normal for off-street running and deep groove crossings, with a few exceptions. There are a few examples of flange running in pointwork on the Croydon Tramlink system, and at least one pair of lift-over crossings, where the wheels on the crossover route run on their flanges across the top of the rail for the through route, in Nottingham.

 

Jim

[martin_wynne]

Correct, Flange running does not seem to have been unusual in mixed gauge track

 

Hi Jim,

 

This is part of Michael Godfrey's excellent model 3-way crossing. I can't see any reason why flange running would be needed, and there is nothing between the rails for them to run on.

 

 

That one article alone is worth a subscription to the Scalefour Society for anyone interested in track. Especially the list of reference sources at the end.

 

regards,

 

Martin.

 

[jim.snowdon]

It's very nice, but the ability to maintain tread support does depend quite critically on the spread between the intersection points of all three routes. Michaels does appear to have arranged (or as likely, the prototype did) to have all three tracks intersect at the same point. The engineers on the GWR do not seem to have been quite so diligent, but equally, may have faced more constraints. Having continuously supported bridge rail would have made the insertion of blocks or plates to support the wheel flanges easier than with chaired track.

 

But, I have come across references in early 20th century track engineering textbooks to the deliberate (as against ad hoc) use of packing blocks in the crossing flangeways to support wheels through crossings. Apart from providing support that depended on who worn the wheel was, there were disadvantages that would appear, ultimately, to have outweighed the benefits.

 

Jim

[Grovenor]

 

This is part of Michael Godfrey's excellent model 3-way crossing. I can't see any reason why flange running would be needed, and there is nothing between the rails for them to run on.

For Michael Godfreys crossing there is continuous support for the straight route using the wing rail, very evident from the shine on the prototype photo.

The GW mixed gauge example is where the flange running was suggested and, in the photo, there appears to be no wing rail to give support.

Regards

[DavidBird]

Spotted this recently, at Tyndrum Lower (or Lower Tyndrum) on the Oban line

 

A welded join in FB rail, and a CWR expansion joint

 

On the other side of the expansion joint a welded FB/BH joint

 

And within 5 metres a fishplated joint in BH (not easily seen but between the two sets of level crossing timbers)

 

Why is there a CWR expansion joint so close to a normal fishplated joint?

 

[DavidBird]

Sorry, double posted

Edited April 26, 2016 by DavidBird

[martin_wynne]

Why is there a CWR expansion joint so close to a normal fishplated joint?

 

The expansion joint is protecting the bullhead track from the stresses in a long length of much stronger connected CWR track. The amount of movement in the expansion joint is more than an ordinary fishplated bullhead joint could accommodate.

 

Martin.

[Donw]

I am fairly sure that some of the Mixed gauge switchwork was designed with some running on the flanges. However Michael's excellent piece of work needs no such support. Trackwork did develop over the years as enginners found better ways to do things.

 

Don

[DavidBird]

The expansion joint is protecting the bullhead track from the stresses in a long length of much stronger connected CWR track. The amount of movement in the expansion joint is more than an ordinary fishplated bullhead joint could accommodate.

 

Martin.

 

Thanks Martin.  So is this arrangement standard for whenever cwr changes to jointed track? And it is only unusual in that this example is clearly visible from outside the fence at a public access point?

[martin_wynne]

Thanks Martin. So is this arrangement standard for whenever cwr changes to jointed track?

 

Hi David,

 

Yes. And where CWR is connected to pointwork.

 

The stresses in CWR track are quite high. Within the middle part of the length, the rail cannot expand and the track is prevented from buckling by the deep ballasting and the ballast piled high at the end of the sleepers. Only the end sections of a CWR length expands. But by more than an ordinary fishplate can accomodate or can be resisted by pointwork. An expansion joint is used to protect such tracks from the CWR stresses.

 

regards,

 

Martin.

[DavidBird]

So is this arrangement standard for whenever cwr changes to jointed track?

 

 

Yes. And where CWR is connected to pointwork.

 

...

 

CWR expansion joints are obviously more common than I thought!

 

Thanks again.

[Grovenor]

 

Yes. And where CWR is connected to pointwork

Except when it is specially strengthened pointwork which is often the case now in CWR main lines.

Regards

[LNERGE]

Except when it is specially strengthened pointwork which is often the case now in CWR main lines.

Regards

I had one at Basingstoke that had been pulled up tight without breathers. A factory made insulated joint had failed (the type you weld in) and they had cut it out and weld a new one in. Cutting only one rail did all sorts of mischief to the points.

[Re6/6]

Opinions please of this firm  http://www.railwaystationtrackplans.co.uk/

 

Thanks

Edited May 21, 2016 by Re6/6

[Budgie]

I see their site offers to download Adobe Acrobat 7.0 for you. This is at least four full versions behind (I am using version 11.0.16).

[martin_wynne]

Opinions please of this firm  http://www.railwaystationtrackplans.co.uk/

 

No contact details on the site, but the site is owned by:

Registrant:        Peter Rodgers        16 North Parade        Matlock        DE4 3NS        United Kingdom

Due to expire on 6th June 2016, it may go offline soon.

 

Same registration details for:

 

 http://www.myrailwayphoto.co.uk

 

 http://www.myrailwaystation.co.uk

 

Some unusual stuff on there, such as:

 

linked from: http://www.myrailwaystation.co.uk/OTHER%20RAILWAY%20PHOTOS/pages/YARMOUTH%20VAUXHALL%20BRIDGE_jpg.htm

 

Martin.