Author Topic: Joint Bar Spacing  (Read 7870 times)

John Kokas

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Joint Bar Spacing
« on: April 13, 2009, 08:17:25 PM »
Why does it appear that joints are in pairs rather than alternating per industry standard?
Is this a 2-footer thing or a "localism" to the WWF?
« Last Edit: April 15, 2009, 08:46:21 PM by Ed Lecuyer »
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John McNamara

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Joint Bar Spacing
« Reply #1 on: April 13, 2009, 10:42:21 PM »
One other thing, why does it appear that joints are in pairs rather than alternating per industry standard?
Is this a 2-footer thing or a "localism" to the WWF?
I wondered about that too when I came to the WW&F; however, I believe it was common on two-footers. The reason was that paired joints cause a vertical bump, while staggered joints cause side-to-side sway. Since the side overhang of the cars is substantial, and the gauge is so very narrow, side-to-side sway must be avoided at all costs.

Mike Fox

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Joint Bar Spacing
« Reply #2 on: April 14, 2009, 08:54:08 PM »
John K. and John M. and who ever else is wondering this. The joints are parallel to prevent the swaying of the cars. With such a large overhang on either side and riding on narrow trucks, the swaying could actually lead to the cars tipping over. This was also done on the original railroad. I don't know who discovered this, but it was used on most if not all two footers.
Mike
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John McNamara

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Joint Bar Spacing
« Reply #3 on: April 14, 2009, 09:57:12 PM »
John K. and John M. and who ever else is wondering this. The joints are parallel to prevent the swaying of the cars. With such a large overhang on either side and riding on narrow trucks, the swaying could actually lead to the cars tipping over. This was also done on the original railroad. I don't know who discovered this, but it was used on most if not all two footers.
I thought my post said that.  ;)

Paul Horky

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Joint Bar Spacing
« Reply #4 on: April 14, 2009, 10:51:18 PM »
Some where I think I saw in Moody's book that none other than George Mansfield himself specfied the pairing of joints. Been a long time since I read the Bible of the profit Moody.

Mike Fox

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Joint Bar Spacing
« Reply #5 on: April 15, 2009, 08:39:30 PM »
Sorry John. I'll have to pay mare attention next time. I thought I read what you typed but evidently I missed a line or four.
Mike
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Joe Fox

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Re: Joint Bar Spacing
« Reply #6 on: July 13, 2009, 07:13:07 AM »
Actualy, the B&SR was staggered. In some of the pictures, you can see that the rail joints are staggered. I think this may have been one of the many reasons why the B&SR had so many frequent derailments.

Joe

Bill Reidy

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Re: Joint Bar Spacing
« Reply #7 on: November 21, 2022, 07:27:33 PM »
Reviving this old thread about parallel versus staggered rail joints.  I happened upon a November 19th isengard.co.uk photo showing track relaying at the Stwlan Dam Road level crossing renewal in Tan-y-Grisiau on the Ffestiniog.  The photo shows parallel joints along a curve. 

I'm guessing this has been and is the common practice in Wales.  I hope John Dobson and our other U.K. friends will weigh in.

I also understand Wales doesn't experience the deep ground freeze/thaw cycles that Maine does, and very likely has better soil conditions, particularly than mid-coast Maine, both of which would affect track alignment over time.

I know early on as the WW&F has been restored staggered joints were viewed as a concern for swaying cars at speed, but after many years of experience we've adopted staggered joints, particularly for curves, to avoid track kinks.

This post doesn't offer an answer for the practice historic Maine two-footers followed for track maintenance, but I think the comparison with Wales standards is interesting to learn.
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John Kokas

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Re: Joint Bar Spacing
« Reply #8 on: November 22, 2022, 10:07:54 AM »
I believe that part of the reason for having staggered joints on curves is because the physical roadbed upon which we run is in far better condition than it ever was during actual operations.  With all the drainage, compaction, road cloth, and ballast that we have added over the years has really stabilized the ground versus pumping mud and cinders.
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John L Dobson

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Re: Joint Bar Spacing
« Reply #9 on: November 22, 2022, 11:37:16 AM »
Reviving this old thread about parallel versus staggered rail joints.  I happened upon a November 19th isengard.co.uk photo showing track relaying at the Stwlan Dam Road level crossing renewal in Tan-y-Grisiau on the Ffestiniog.  The photo shows parallel joints along a curve. 

I'm guessing this has been and is the common practice in Wales.  I hope John Dobson and our other U.K. friends will weigh in.

I also understand Wales doesn't experience the deep ground freeze/thaw cycles that Maine does, and very likely has better soil conditions, particularly than mid-coast Maine, both of which would affect track alignment over time.

I know early on as the WW&F has been restored staggered joints were viewed as a concern for swaying cars at speed, but after many years of experience we've adopted staggered joints, particularly for curves, to avoid track kinks.

This post doesn't offer an answer for the practice historic Maine two-footers followed for track maintenance, but I think the comparison with Wales standards is interesting to learn.

Traditionally the FR used parallel joints and clasp fishplates, and had little trouble with kinks, largely thanks to the use of 48-50lb double-head or bullhead rail, which curves quite easily compared with the equivalent weight of flat-bottom. When we relaid the WHR, using the 60lb or 30kg/metre flat-bottom rail that is still commercially available for mining and other industrial use, we found that it was necessary to get this rail pre-curved by a specialist rolling mill before it was laid on anything but the gentlest curves. Staggered joints (and steel, spade-ended ties) were also used on the sharpest curves to prevent movement. Parallel joints are still used where curvature is slight to avoid the unpleasant rocking motion that can be induced in carriages if dips occur at staggered joints .
« Last Edit: November 22, 2022, 04:40:09 PM by John L Dobson »
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Benjamin Richards

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Re: Joint Bar Spacing
« Reply #10 on: November 22, 2022, 01:39:38 PM »
I get asked about joint bars with surprising frequency when I'm on train crew. Or rather, "Why does it bump so much?" I knew the bit about sway, but not the bit about kinks. Thanks for helping me be better informed!

Wayne Laepple

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Re: Joint Bar Spacing
« Reply #11 on: November 22, 2022, 05:44:28 PM »
Some years ago, I had occasion to ride a British Railways diesel multiple unit train on a branch line from Cambridge to Hull. The line was laid with opposing joints, and even the relatively lightweight dmu bounced and bounced and bounced the entire distance. It was an uncomfortable ride. In this country, the old Cedar Rapids & Iowa City interurban line was also laid with opposing joints, and after its lightweight but high speed interurban cars were retired and sold to various museum, restorationists discovered that the pounding on the joints actually drove the truck bolster up through the floors of the cars!