Bridge without guard rails. Cover of March Trains

[K. P. Harrier]

Some Case Examples

These two new Los Angeles & Salt Lake (Union Pacific) bridges are in Riverside, CA; the right one a shoofly bridge, the left a future permanent one under construction.  The new bridges were necessitated by the 91 Freeway’s widening.  Traditional guard rails are present.

The Grand Terrace, CA area new BNSF Transcon trusses, also necessitated by another freeway widening project, this one the I-215 Freeway.  The trusses have NO guard rails.

A blown-up view:

The trusses seem to have an inset to keep any wayward railcars on the track alignment, but lack anything to keep wayward railcars from hitting the trusses immediately in front of the bridges.

It is hoped the above views will be of assistance in evaluating the subject matter at hand.

Best,

K.P.

[Euclid]

cx500

 

Euclid

A derailed truck can run for miles without causing a pileup.  But the chance of it causing a pileup increases when it crosses a bridge, either due to tearing up the deck or fouling any structure above the track elevation.  The guardrail is intended to prevent that. 

But a guard rail can also cause a truck to pileup the train as well as prevent it. There is a variety of possible reactions when a derailed truck encounters a guardrail.  I conclude that is why we see installations of totally converging guardrails, partially converging guardrails, non-converging guard rails, single guard rails, and no guardrails.    

 

 

 

 

Sorry, but I disagree with much of what you claim.  A derailed truck, especially if it is only one axle or a trailing truck, can run for miles.  Then it hits a turnout, or sometimes a crossing, and the pile-up starts.  A bridge deck does not present anything different from regular track so there is no greater chance of it piling up there.  What is different are the potential consequences from damage to or destruction of the bridge should the pile-up happen there.  The guard rails are to protect the structure.

If the guard rail causes a truck to pile up the train as you suggest, that truck was already far enough from the rails, or skewed enough, that the pile up was already imminent.  With a bit of luck, guard rails might guide the truck into a straight alignment back close to the running rails until past the structure.

Your conclusion is based on faulty assumptions.

 

 

A bridge deck may present the same support as the regular track, but not necessarily.  I agree that one purpose of the guard rail is to prevent the pileup from damaging the bridge if the pileup just happens to occur on the bridge even though nothing about the bridge contributed to the cause.  But I also believe that the bridge can become the cause of a derailment that would not have happened had the derailed car not been dragged over the bridge. 

The guardrail protects against both of those possibilities, and in the case of the latter, the guardrail protects not only against damage to the bridge, but protects against the damage of the pileup itself.

A guardrail might guide a derailed truck back into alignment for safe passage across the bridge, as you say.  But it also might grab the truck so hard in the realignment that it causes the pileup that would not have necessarily happened without the guardrail.  

The guardrail itself, while intended to prevent a problem, can be snagged in a way that tears it out and the resulting damage causes the train to pileup when it might not have done so if there were no guardrail to snag.  So, for example, the guardrail itself can be the key difference between a bridge support and the support of regular track that makes the bridge support more likely to turn a derailed and dragging car into a pileup than does the regular track.     

[cx500]

Euclid

A derailed truck can run for miles without causing a pileup.  But the chance of it causing a pileup increases when it crosses a bridge, either due to tearing up the deck or fouling any structure above the track elevation.  The guardrail is intended to prevent that. 

But a guard rail can also cause a truck to pileup the train as well as prevent it. There is a variety of possible reactions when a derailed truck encounters a guardrail.  I conclude that is why we see installations of totally converging guardrails, partially converging guardrails, non-converging guard rails, single guard rails, and no guardrails.    

 

Sorry, but I disagree with much of what you claim.  A derailed truck, especially if it is only one axle or a trailing truck, can run for miles.  Then it hits a turnout, or sometimes a crossing, and the pile-up starts.  A bridge deck does not present anything different from regular track so there is no greater chance of it piling up there.  What is different are the potential consequences from damage to or destruction of the bridge should the pile-up happen there.  The guard rails are to protect the structure.

If the guard rail causes a truck to pile up the train as you suggest, that truck was already far enough from the rails, or skewed enough, that the pile up was already imminent.  With a bit of luck, guard rails might guide the truck into a straight alignment back close to the running rails until past the structure.

Your conclusion is based on faulty assumptions.

 

[tree68]

I've only got 15 years on Doug.

Pick up sticks and jack sticks are essentially the same thing (and closely related to Jenga in that the goal is to move one piece without affecting any others).  I suspect it's a regional name that I picked up in my travels.  Kinda like pop/soda/Coke.

Who says the Trains forums aren't educational?

[Deggesty]

Doug, I will confess to having 30 years on you. Perhaps the thought of "scattering like jackstraws" just hasn't been heard in enough places in the last 40-50 years? I don't know when I had heard or seen it. No, Larry is not as old as I am. He's trying, but he has not made it yet.

[Murphy Siding]

     I don't know it's an age thing.  I'm 55 and I've never heard of the game of jack straws.  Maybe it's a regional thing? As a kid, we had pick-up-stix.  That was a similar game, but the sticks were bright plastic stips about the size of fat spaghetti.

[challenger3980]

Murphy Siding

 

tree68

I would opine that in the case of a catastrophic "jack straws" derailment, guard rails (whatever their form) would make little difference.

On the other hand, one truck or car dropping off the rails should be kept more or less in line whilst on the bridge, lessening the possibility of that "jack straws" derailment, at least until they clear the bridge.  

I'm sure that there are plenty of stories available in which guard rails either saved the day or failed their task miserably.

 

 

 

 

  I didn't want to look like a dumby, so I googled jack straws derailment.  All I could find was coupons for Jack Straw Pizza.  Can you explain jack straws derailment for this dumby please?

 

 

 

Murphy, don't feel bad, I'm 50 years old, and have been a a train nut, er, I mean Rail Fan, all my life, and I have never heard that term either.

Doug

[Deggesty]

tree68

 

 

Deggesty

I believe that Larry is referring to a derailment in which cars are scattered all over the landscape.

 

 

Scroll down a little further after searching for "jack straws" and you'll find this definition.

Hence "they were piled up like jack straws."

Including a pile of lumber in the front....

 

Yup, they're scattered like jackstraws.

[tree68]

Deggesty

I believe that Larry is referring to a derailment in which cars are scattered all over the landscape.

Scroll down a little further after searching for "jack straws" and you'll find this definition.

Hence "they were piled up like jack straws."

Including a pile of lumber in the front....

[Euclid]

A derailed truck can run for miles without causing a pileup.  But the chance of it causing a pileup increases when it crosses a bridge, either due to tearing up the deck or fouling any structure above the track elevation.  The guardrail is intended to prevent that. 

But a guard rail can also cause a truck to pileup the train as well as prevent it. There is a variety of possible reactions when a derailed truck encounters a guardrail.  I conclude that is why we see installations of totally converging guardrails, partially converging guardrails, non-converging guard rails, single guard rails, and no guardrails.    

[Deggesty]

I believe that Larry is referring to a derailment in which cars are scattered all over the landscape.

[Murphy Siding]

tree68

I would opine that in the case of a catastrophic "jack straws" derailment, guard rails (whatever their form) would make little difference.

On the other hand, one truck or car dropping off the rails should be kept more or less in line whilst on the bridge, lessening the possibility of that "jack straws" derailment, at least until they clear the bridge.  

I'm sure that there are plenty of stories available in which guard rails either saved the day or failed their task miserably.

 

  I didn't want to look like a dumby, so I googled jack straws derailment.  All I could find was coupons for Jack Straw Pizza.  Can you explain jack straws derailment for this dumby please?

[tree68]

I would opine that in the case of a catastrophic "jack straws" derailment, guard rails (whatever their form) would make little difference.

On the other hand, one truck or car dropping off the rails should be kept more or less in line whilst on the bridge, lessening the possibility of that "jack straws" derailment, at least until they clear the bridge.  

I'm sure that there are plenty of stories available in which guard rails either saved the day or failed their task miserably.

[Euclid]

I generally conclude that there are differing theories about the design of guard rails, including omitting them. 

[cx500]

Some folks felt that the 4"x8" spacer timbers on the outside of the running rails served the same purpose as the inside Jordan guard rails.  Since many roads switched, that suggests when needed guard rails proved to be a more effective design.  No doubt found out the hard way, like many engineering advances.

 

[Norm48327]

Heartland Division CB&Q

Everybody .... Thanks for commenting 

Murphy Siding ... Yes I put it on the MR Forum because model railroaders might want to know they may not need to include gurage rails on model bridges.

 

I have no idea why Kalmbach moved my thread. 

 

Oh well. 

 

Notify the moderators. They've been doing some stange thing lately.

[Euclid]

There must be a fine line that divides prototype practice from modeling prototype practice. 

[Heartland Division CB&Q]

Everybody .... Thanks for commenting 

Murphy Siding ... Yes I put it on the MR Forum because model railroaders might want to know they may not need to include gurage rails on model bridges.

 

I have no idea why Kalmbach moved my thread. 

 

Oh well. 

[Murphy Siding]

It looks like this thread got bounced over here from the Model Railroading Forum?  I bet those guys wonder where it went.

[tomikawaTT]

Jeff hit the key point.  Guard rails are primarily meant to keep derailed cars lined up with the running rails, to avoid collateral damage to bridge structure and other things adjacent to the tracks.  Their use is dictated by the standards for the particular railroad.

Looking at two photos of my prototype:

1. Heavy guard rails, one on the outside edge of each of the double tracks under catenary.  I presume the purpose is to keep a derailed car from collecting a train passing in the opposite direction.  If it wants to go outward (and take out the catenary support structure,) no problemo.
2. dual guardrails on a deck girder bridge - normal configuration, but the rails look like something swiped from an abandoned mine.  Maybe 25#, and spiked every fifth tie.  No heavy timber at the end of the ties, either, just a strip of strap iron secured with what appear to be 20-penny nails.

Apparently having a ballasted deck does not eliminate the need for guard rails.  I've seen them on through girder bridges with ballasted decks.

The longest continuous guard rails I personally encountered ran from the mouth of a tunnel about a kilometer long, out the other end, across a concrete arch bridge, into a second, shorter tunnel, ending at that tunnel's far portal.  Total length, close to two kilometers.

Chuck (Modeling Central Japan in September, 1964)

[jeffhergert]

I was told that guard rails on bridges are not required on lines that don't regularly handle passenger trains.  Even if not required, railroads may still have them on some bridges.  Especially where a bad derailment could damage the bridge structure.

Jeff  

[wabash2800]

I haven't seen the photo, but regardless of their construction, guard rails or timber guards aren't used as much as they were at one time. The same thing can be said about derails at interlockings.

Victor A. Baird

Fort Wayne, Indiana

 

[floridaflyer]

Regardless of the type of guard that can be used, steel, wood or whatever, there doesn't appear to be anything other than the gage rails.

[BigDaddy]

I don't get the mag, but on their home page, they have a selection of 5 photos at the top.  #4 is a FL East Coast on a bridge without a guard rail. 

http://trn.trains.com/

[mbinsewi]

OOOHHHHH, THOSE guard rails.  Never mind...

[BroadwayLion]

The GUARD rails for the tracks are those rails about four to six inches insisde of the gauge. They come together to a point or clse to it off of the bridge.

They will not keep the train on the tracks, the idea is to keep a derailed truck fro wandering off of the bridge but to keep the load on the bridge.

 

But the guard rail need not be a rail at all, nor does it need to be within the gauge. Wooden timbers running parallel to the rails and spiked to the ties will serve the same purpose.

 

ROAR

[mbinsewi]

I have the issue right next to me, Gary.  There is a very substantial guard rail along the walk-way, so a train crew and maintanence people can walk the bridge.  Are you thinking there should be a guard rail substantial enough to hold back a derailed train?

I don't think I've seen that on any type of a trestle bridge.  I was reading the article about the "Edgewood cutt-off", and the train the author was part of, went into emergncy breaking on the bridge that crosses the Ohio river, and there wasn't even a walkway on that bridge, just 100' of air between the train and the river.

Mike.

EDIT: Actually, as soon as I seen the bridge, I wanted to model it !

[Heartland Division CB&Q]

Evidently, bridge guard rails are not needed anymore. The cover photo of March Trains has a CSX coal train crossing a bridge, and there are no guard rails in the bridge track. Why is that the case ?