Murphy Siding Quenten- In our part of the world, I believe it's the road salt that kills the concrete bridges. I'd hope that road salt wouldn't be too much of an issue on a railroad bridge.
You are correct.....In fact, the structure I related to in my previous post is at a connection {joint}, in the road surface on the bridge and the salt {brine}, has leaked down onto the ends of the prestressed horizonal beam ends I spoke of, and the result is the concrete has come off the beam ends to the point exposing the re-bar and it too is all rusted.....and with just a half a foot of the beam resting on it's support.....
And of course, not much chance of salt getting on a RR bridge in like amounts.
Quentin
Am I right in thinking that the railroads must have regular bridge inspectors, or is that part of the job of the MOW gang?
Thanks to Chris / CopCarSS for my avatar.
Quenten- In our part of the world, I believe it's the road salt that kills the concrete bridges. I'd hope that road salt wouldn't be too much of an issue on a railroad bridge.
With much of the technical reasons already listed, one might conclude the steel railroad structures, especially after 1900 seemingly were "overbuilt" to the point it will or would take extraordinary circumstances to bring them down.
One can see abandoned RR bridges still standing in many locations, some that have been in that state for at least 60 years....{one I'm thinking of back in my home area of Pa.}. Here in Muncie, several on abandoned lines are standing and one pair...{end to end}, a thru truss structure look macho enough to stand another 100 years if the supports remain underthem....One masonary structure at the middle of the two spands and of course each concrete base structure at each end.
Again here in Muncie, a concrete {bypass highway}, bridge with prestressed horizonal beams under it....already looks scary.....and they have been built perhaps no more than 20 years ago. The ends of the prestressed beams are placed on their supports and the concrete is flaked away to the point the re-bar is visible and they only overlap onto the supports by about 6 or so inches.
They concerned me so much, several years ago, I stopped and took photos of the situation and sent them to our local officials, and their reply back to me was they were scheduled to renovate that bridge next season.....That was several years ago. I have photos but sorry, can't put them on here....They sure look scary to me.
My only point is, I believe RR bridges go far beyond this type of design and will not be compromised in a decade or so after they are built.
Johnny, those are excellent questions. I've seen nothing that addresses any of them.
The nominal loading of the rocket motor cars would have been on the order of Cooper's E-77 - 500,000 lbs./ 65 ft. That's pretty heavy, but not unheard of, esp. for any kind of modern traffic.
But I recall that the train had used that line before, and sure enough -
"A spokesman for the manufacturer, Bryce Hallowell . . . said the train was taking the same route to the Kennedy Space Center that has been used for 30 years or more." (from DEMOPOLIS, Ala., May 2, 2007 - ''Train Carrying NASA Boosters Derails - Freight Train Derails In Alabama After Bridge Collapse; 6 Injured'', at - http://www.cbsnews.com/stories/2007/05/02/national/main2754231.shtml )
There, I suspect, is the true answer - a variation of "We've always done it that way". If anybody ever actually carefully looked at that route, and considered and/ or rated that bridge, it might have been 30 years ago - and they're long gone, as is the validity of that assessment. So this appears to be yet another cautionary tale about the need for checking out the qualification or certification of something critical to an operation - ''The Emperor has no clothes'' kind of a thing - and leaving nothing left to chance, kind of like airframe ratings, and nuclear plant quality assurance procedures, etc. And rating the structural capacity of old timber bridges - and the many subtle and subjective judgments necessarily involved therein - is more of an art form than a mature science. See the brochure for an upcoming course/ seminar on Timber & Steel RailRoad Bridges next week at the University of Tennessee in Knoxville at -
http://ctr.utk.edu/ttap/training/brochures_2010/TimberSteelRRBridge_Knox.pdf
- Paul North.
Carl
Railroader Emeritus (practiced railroading for 46 years--and in 2010 I finally got it right!)
CAACSCOCOM--I don't want to behave improperly, so I just won't behave at all. (SM)
Paul_D_North_JrFRA's investigation determined that the probable cause of this accident was bridge failure, caused by the rotation of several of the timber bents of Bridge 48.8, under a train load that exceeded the normal load capacity of the bridge.
Paul North: There are several questions not asked or answered in this report. I'll go in order of occurrence.
1. Had other rocket booster trains also gone over this bridge in the past?
2. If so when was the last occurence?
3, If so did past trains have idler cars?
4. If so had there been a major weather event such as high water that may have caused lowering of the actual loads?
5. Why did UP not use idler cars even though their track could take this loading and did they cross any bridges on UP that may have the bridge's cooper ratings exceeded?
6. Was UP notified by M & B of the load limit? I thought that was always done before and oversize/ overweight loads?
7. Did M&B ETT show the load limit?
8, Why did M&B not insert idler cars? Did they think they were not as heavy as they turned out? * 8 axels over that short of a span certainly should have rung bells as to probably exceed cooper ratings.
9. Why run the first train using very high loads over the bridge when another train was there?
10. Why run passengers over the bridge?
11. Why various officals stand so close that they had to run when bridge started collasping?
Well----- we will never hear all these answers.
Paul, looking at your report on the collapse of the M&BR bridge, I wonder: what was the Cooper rating of the bridge? Who selected that routing? Why was that routing selected? Did anybody employed by the M&BR who was involved in accepting the train realize what load would be placed on their line?
As to the collapse of the AT&N bridge, it may well have been caused by poor, if any, maintenance. Had the SLSF wanted to abandon the line between Aliceville and York, and so did not maintain the bridge (for many years, the twenty miles of the AT&N north of Aliceville was ten-mile-per-hour track, with very little, if any maintenance performed; it has now been abandoned for several years.)? As it is now, very little of the AT&N remains.
Johnny
blue streak 1 What was the reason of the collaspe of the ex WP bridge near Palisade, Nv last year or 2008?
Looking back at that thread - UP Derailment & Bridge Collapse on Overland Route - started Dec. 28, 2008 at -
http://cs.trains.com/trccs/forums/p/144348/1604384.aspx
it appears that the derailment happened first - 'root cause' of what, I don't know - and damaged the bridge so badly that it collapsed a few hours later.
See also http://www.jimdobbasinc.com/ -
"Palisade Canyon, NV—December 2008
A freight train derailed in a remote area along the Humboldt River triggering a bridge collapse and disruption of the Union Pacific Railroad’s East- West mainline."
and -
"The train was passing through an 875-foot tunnel when the derailment occurred. Three cars derailed inside the tunnel and at least a couple of cars ended up in the river, [rail company spokeswoman Zoe] Richmond said."
From UP Bridge out in Paliside Canyon at - http://www.trainorders.com/discussion/read.php?1,1834175 - and -
carlin derailment at - http://www.trainorders.com/discussion/read.php?1,1834963
Murphy Siding Other than last year, when a bridge (or trestle?) on a shortline railroad collapsed while hauling something big for NASA, are railroad bridge failures rare?
Well, I had a nice post on this put together - then MS Internet Explorer crapped out on me. So here goes again -
Here's the link to the FRA report on this - it's 10 pages, about 265 KB in size:
Headquarters Assigned Accident Investigation Report HQ-2007-24
M & B Railroad, LLC - Myrtlewood, AL - May 2, 2007 - at -
http://www.fra.dot.gov/downloads/safety/Accident_Investigation/2007/hq200724.pdf
Short version is that a poorly designed/ constructed old trestle - without any longitudinal bracing, in poor condition - some of the bents were way out of plumb, in the midst of emergency and temporary repairs, and seriously overloaded by exceptionally heavy cars, just gave way.
From the report [emphasis added - PDN]:
Each of the eight cars carrying rocket booster motors was equipped with eight axles in a span bolster truck arrangement, in which each car was carried on four standard freight car trucks, with the two trucks at each end of the car supporting a span bolster which in turn carried the car body. The gross weights of these eight cars ranged from 462,800 pounds to 505,600 pounds.
The gross weight of a common free-running freight car on four axles is 263,000 pounds, and most large railroads permit the operation of four-axle cars weighing 286,000 pounds. Although the eight heavy cars in this train were carried on eight axles rather than four, the concentration of eight axles within the 65-foot length of each of the cars presents a severe load condition to a bridge.
MNBR Train S100-29 was the first revenue train to operate on the bridge after cribbing had been placed under the intermediate spans. The locomotive engineer reported that when the train's locomotives had entered onto the bridge by about 200 feet from the west, or entering, end of the bridge, he heard a loud "pop." Initial observations and reports by MNBR indicate that the bridge first failed near Bent 20 under three of the 8-axle flat cars carrying the rocket boosters. When that portion of the bridge failed, it appears the stringers to the east of Bent 20 uniformly pulled toward the west, toward the rear of the train, and off of the end bent (Bent 55) cap. That loss of support for the stringers and track on the east end caused the bridge to fail at a second location, under the locomotives, thus derailing the locomotives and the passenger coach. A more definite analysis of the bridge failure was prevented by the destruction of the bridge and its components in the accident.
PROBABLE CAUSE AND CONTRIBUTING FACTORS:
A contributing factor to this accident was the initial out-of-plumb condition and lack of longitudinal bracing of the timber bents of Bridge 48.8.
FRA's investigation determined that the probable cause of this accident was bridge failure, caused by the rotation of several of the timber bents of Bridge 48.8, under a train load that exceeded the normal load capacity of the bridge.
Around 1977 a wooden trestle about 1/2 mile east of Magnolia MN collapsed under an eastbound C&NW train going from Sioux Falls to Worthington. Most of the cars on the train were loaded with rock and a few ended up in the creek bed. I was 17 at the time and had just bought my first camera, so I do have some poor quality pictures of the mess. The trestle was rebuilt.
That's the one which Chad Thomas was kind enough to provide some photos of - and I believe there were also some from another local railfan or newspaper, etc. I recall that it was of the 'derailed-car-hits-diagonal-portal-member' variety, which is almost always fatal to the bridge - or, possibly a shifted load, though I haven't seen anything in print.
By the way, as to the original question posted by Murphy - my understanding is that there was some extensive maintenance work being performed on that wooden trestle at the time, though again I've seen nothing in print yet. That doesn't mean it was the cause - but I haven't seen any other plausible cause identified, either.
What was the reason of the collaspe of the ex WP bridge near Palisade, Nv last year or 2008?
Mainly - and very generally, with some notable exceptions - because the railroads take better care - or at least, precautions, such as speed limits and load limits, etc. - with the ones that are operated over. Also, there are only a limited group of people involved with them - such as the train crews - who are real interested in their own safety and condition of the bridges. Accordingly, appropriate special instructions and precautions - such as using spacer cars between locomotives or heavy cars, etc. - can also be implemented.
If a major bridge is in poor condition - and the railroad has exhausted the quick and easy repairs and stop-gap measures such as the above - the railroad is then faced with the hard decision of whether to repair the bridge, or abandon the line, or maybe serve the far end only via another branch or trackage rights from another railroad, etc. Usually by that point the economics of the line generally and elsewhere are so poor that the decision is relatively easy - there's a lot more than 1 bridge that is in poor condition. That's essentially part of what happened with the ex-Erie RR Kinzua Viaduct in north-central Pennsylvania. Even the Knox & Kane tourist railroad wouldn't run across it in recent years, and when most of it collapsed during a severe windstorm/ tornado several years ago - in the midst of a state-funded repair project, ironically enough - the short line threw in the towel and abandoned the line.
In contrast, there are many abandoned lines - now rail-trails - that cross over huge bridges that are still in excellent condition. Think of the ex-Milwaukee Puget Sound Extension, the former Western Maryland along the Potomac River, and others. I had one ConRail Bridges & Buildings supervisor tell me that the 3 bridges along the Bushkill Creek in Northampton County that I was asking about for a rail-trail never gave him any trouble, and he had no doubts about them - it was always the embankments on either side that washed-out, etc.
The very recent, excellent, and thorough - if commensurately lengthy, though - report that Jamie provided the link to above (thanks ! ) -
http://www.raib.gov.uk/cms_resources.cfm?file=/100203_R022010_Stewarton.pdf
is instructive in several ways. That was a short bridge over a country lane that was well over a century old, and failed due to unrepaired corrosion of the girders - about a month before it was scheduled to be repalced anyway. For the purpose of your question and this thread, the following several paragraphs from it are pertinent [emphasis added - PDN]:
From the British Department for Transport's Rail Accident Investigation Branch ''Report 02/2010 - February 2010 - Derailment of a freight train near Stewarton, Ayrshire - 27 January 2009",© Crown copyright 2010, pages 31 and 32 of 94 (approx. 6.87 MB in size):
Discounted causes
116 There were a series of collapses involving underbridges with cast iron beams in the 19
117 More recent railway underbridge collapses have occurred, but these have generally been the result of weakening due to external factors such as
Is it rare because the bridges in the worst condition were on lines that were taken out of service, or because the railroads take better care (?) of the the ones they still have?
I’d say they are rare, but yes, they do “happen.”
Justin
The road to to success is always under construction. _____________________________________________________________________________ When the going gets tough, the tough use duct tape.
I'd say that yes, they are "rare'' - however that term is defined statistically. I suppose that either the FRA or an AREMA Committee does track such events, though.
The purely 'structural failure' of a well-maintained bridge to carry a design train load is near zero. There's almost always some other outside factor that damages a key component and which then leads to the failure, such as (in no particular order):
- Being struck by a barge, ship, or truck underneath, which cripples a bent, pier, girder, or truss member, etc.;
- Being struck by a shifted load or derailed car on top, esp. the end portals of through truss bridges;
- Undermining by floodwater scour, or a landslide or other subsurface geotechnical failure;
- Inadequate maintenance, which leads to deterioration and loss of design strength, in a variety of ways;
- Goofs by the personnel who are maintaining or upgrading the bridge - lack of or improper shoring, bracing, 'falsework', or other temporary measures while the work is being performed;
- Fire - accidental - sometimes by welders, or intentional.
In short, those failures are either preventable with reasonable care, supervening acts of nature or man, or random chance.
I can think of two bridge failures here in British Columbia, both were wooden bridges owned by Canadian National. A bridge collapsed under a freight train, which resulted in the death of two CN employees on May 14, 2003 near McBride, British Columbia.http://www.tc.gc.ca/eng/mediaroom/releases-nat-2004-04-h031e-3527.htm
The other was on the line to Kitimat. It happened as the wood towers were being replaced with steel, and a crane was on the bridge at the time.
Offhand, the only bridge failure I really remember was that of the AT&N's bridge across the Tombigbee River, just below Cochrane, Ala. I do not remember the year, but it was about 1970. Afterwards, I talked with the conductor of the train that had just gone across before the bridge fell into the river. He was pretty calm about it when we talked, but it must have been quite a shock to hear and watch the bridge fall right after the train left it. The bridge was never replaced.
The train was an Amory, Miss., to Mobile, Ala., that came into Aliceville, Ala., on the SLSF. The new routing was SLSF through Aliceville to Boligee, Ala., thence AGS to York, Ala., and then AT&N to Mobile. At first, the SLSF crews said that they should operate the Mobile trains as far as Boligee, but the AT&N crews were given seniority rights for the Mobile trains Aliceville-Boligee. Aliceville to York was only about three miles longer through Boligee than it was on the AT&N.
Other than last year, when a bridge (or trestle?) on a shortline railroad collapsed while hauling something big for NASA, are railroad bridge failures rare?
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