https://bridgehunter.com/mt/mineral/bh61400/
MidlandMikeWhat is the bridge over? If its over a road, the highway authority would not approve a building over it. If the bridge is over a waterway, you would probably not get an environmental permit.
Bridge over troubled waters!
Never too old to have a happy childhood!
What is the bridge over? If its over a road, the highway authority would not approve a building over it. If the bridge is over a waterway, you would probably not get an environmental permit.
MC,
Your points are well taken. In my late twenties I was a land title examiner and I got handed every metes and bound descriptions. The company had a surveyor on retainer and I frequently had to rely on him to be certain descriptions closed. If they didn't we wouldn't insure title to the land in question.
Your knowledge of both surveying and railroading is invaluable. I'm sure Farnsworth compensates you well for that.
Norm
(1) You can get clear title to the land and improvements? (First Hurdle - or is the "owner" also selling off parts of the Brooklyn Bridge? Very possibly a licensed surveyor and competent title examiner/ real estate attorney will need to get involved)
(2) Find a good licensed structural engineer and probably also an architect (Second Hurdle) Do NOT just deal with an architect.
(3) Have fun dealing with the local planning/zoning/building department if you get past (1) and (2) (Third-Fifth Hurdles)
(4) $$$$$$$$$$$$$$$$$$
Read through this post and its really informative. I pose a question for help. I love recreation and found a piece of land that includes a beautiful abandoned MILW Bridge.
What can I do to see if i can build a structure on it?
How can I insure it?
Anyone on here ever done this?
At 1.3 miles, the Poughkeepsie Bridge is probably a little longer (and definitely higher!). And it's open at both ends, I've been told!
(Still, Number Two isn't bad, in this case!)
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)
Modelcar samfp1943: One of the things that has surprised me in this Thread is the failure of the former Big 4 Railroad bridge at Louisville, Ky over the Ohio R. to be noted. It was essentailly abandoned in 1969 and the aproach spans were removed and scrapped. It was then just left spanning the Ohio R. going nowhere. The adjacent cities in Kentucky and Indiana (Louisville and Jeffersonville) tended to use it to launch fireworks from on occasions. ......That is really a great RR bridge....Great in size. I'm sure Walt can tell us the update on it. Believe it has a new purpose. A walking / biking route across the river. Walt sent me photos of the work on one end of it with a new winding ramp to reach up to make access to it. I have passed under it on the river, and from that prospective it really appears to be a mammoth structure. Not sure just what the original purpose of this thread was, but if it was just commenting on known abandoned RR bridge structures still in place....I have one to mention: Location...near Hollsopple, Pa. over a river / stream. It would have been owned by B&O. The branch location was from near Hollsopple, to Jerome, Pa. a coal branch line. The 2 span bridge is of the "thru Steel Girder" type.... I know it has been abandoned now for around 60 years. One support concrete / stone in the center. It is still in place. Tracks long gone....I've never stopped to take a pic. of it when we're back in our home area there of Pennsylvania, but I'll certainly put it on the list of "things to do", with the next visit. It is near the very large Quemahoning Dam {few miles north of it generally}, and I"m sure it is visible on a good satellite image . There has been several floods in that area since it's abandonment, but it still stands.
samfp1943: One of the things that has surprised me in this Thread is the failure of the former Big 4 Railroad bridge at Louisville, Ky over the Ohio R. to be noted. It was essentailly abandoned in 1969 and the aproach spans were removed and scrapped. It was then just left spanning the Ohio R. going nowhere. The adjacent cities in Kentucky and Indiana (Louisville and Jeffersonville) tended to use it to launch fireworks from on occasions.
One of the things that has surprised me in this Thread is the failure of the former Big 4 Railroad bridge at Louisville, Ky over the Ohio R. to be noted. It was essentailly abandoned in 1969 and the aproach spans were removed and scrapped. It was then just left spanning the Ohio R. going nowhere. The adjacent cities in Kentucky and Indiana (Louisville and Jeffersonville) tended to use it to launch fireworks from on occasions.
......That is really a great RR bridge....Great in size. I'm sure Walt can tell us the update on it. Believe it has a new purpose. A walking / biking route across the river. Walt sent me photos of the work on one end of it with a new winding ramp to reach up to make access to it.
I have passed under it on the river, and from that prospective it really appears to be a mammoth structure.
Not sure just what the original purpose of this thread was, but if it was just commenting on known abandoned RR bridge structures still in place....I have one to mention: Location...near Hollsopple, Pa. over a river / stream. It would have been owned by B&O.
The branch location was from near Hollsopple, to Jerome, Pa. a coal branch line. The 2 span bridge is of the "thru Steel Girder" type....
I know it has been abandoned now for around 60 years. One support concrete / stone in the center.
It is still in place. Tracks long gone....I've never stopped to take a pic. of it when we're back in our home area there of Pennsylvania, but I'll certainly put it on the list of "things to do", with the next visit. It is near the very large Quemahoning Dam {few miles north of it generally}, and I"m sure it is visible on a good satellite image .
There has been several floods in that area since it's abandonment, but it still stands.
I'm not totally sure as to what this thread is about either, Quentin posted about the "Big Four Bridge" in Louisville, Ky. Most of what I know it was built in 1895 (completed) and rebuilt in 1929. The last train over the bridge was in 1968-1969. (depends on whom you talk to.) The approaches were taken down there after, making it into the mid 70s until that was complete.
(I moved from E. Ky. to Louisville in 1973, and some of those approaches were still up until about 1975.)
Over the years, several organizations have claimed to own that bridge, several years ago, via whatever means necessary, the city of Louisville has finally claimed title to the bridge. Right now, it's being "converted" into a bike/walking trail/path between here and Jeffersonville, In.(when complete, I believe the longest in the U.S., at just over a mile.)
The first photo attached, is the circular walkway on the Lou. side; Jeffersonville has yet to come up with plans for their side. Second photo is a view of the bridge from the Ky. Side, looking towards In. At the last I've heard/seen, the bike/walkway is scheduled to be completed sometime in 2012; several years after the original completion date.
(seems they had to pull some monies from the two proposed highway bridges over the Ohio to finish this project.)(?)
Being Crazy,keeps you from going "INSANE" !! "The light at the end of the tunnel,has been turned off due to budget cuts" NOT AFRAID A Vet., and PROUD OF IT!!
.....Right on Paul....Just a short distance from "home", Stoystown. I don't know why I've never stopped there to take a pic. It certainly has stayed in place thru lots of extremes since it's abandonment.
The last train I remember seeing going up that branch to Jerome, with coal cars, had a steam engine on the point, and I'd say that would be about 1951.
Quentin
'Bout here: N 40.20045 W 78.93686 On east side of PA Rt. 601 = penn Ave., about 0.8 mile SSW of junction with PA Rt. 403 = S. Main St. at Hollsopple, 3/4 mile SW from center of Benson, 1 mile SE of US 219, about 1.2 miles north of the Quemahoning Dam, and crossing the Stoneycreek River just below / north of where the Quemahoning Creek flows into it, all about 8 miles south of Johnstown.
Thanks for that reference - I'd not heard or seen anything about that one before.
- Paul North.
samfp1943 One of the things that has surprised me in this Thread is the failure of the former Big 4 Railroad bridge at Louisville, Ky over the Ohio R. to be noted. It was essentailly abandoned in 1969 and the aproach spans were removed and scrapped. It was then just left spanning the Ohio R. going nowhere. The adjacent cities in Kentucky and Indiana (Louisville and Jeffersonville) tended to use it to launch fireworks from on occasions.
It has quite a hilstory from it construction onward.
Here is an interesting link: http://www.ominousweather.com/Big4Bridge.htmler
FTL:"...Construction began on October 10, 1888. The Big Four Bridge would be the only Louisville bridge with serious accidents during its building; thirty-seven individuals died during its construction..."
Same thing with the bridges the C&NW had on my part of same lines (Pulaski, Gillett, Scott Lake) Not that many spans long enough to rate plate girders in the first place, at least north of Green Bay but just south of Gillett was a four span bridge with the same type of masonry piers (with an additional span and concrete pier replacing wooden trestle work sometime later-the 1920's, I'd think). When the line was abandoned (in segments) all the girder bridges were left in place (including some additional trestlework replacement spans on other bridges).
By way of contrast, when the Gillett-Shawano-Clintonville line was abandoned in the late 30's, the plate girder bridges were removed. Different times, different circumstances.
Seems like all the threads I find interesting are dead.....o well
The railroad in my town has been gone for 30 years but one bridge still stands and I'm not sure why, since all the smaller ones have been removed. There was 1 bridge on each side of town that spanned a small creek and they are both removed, but one bridge 5 miles out of town over the local river is still standing and is at least 90 years old......
I havnt gotten a look from up top so I'm not sure if the rails have been removed from the bridge itself but I'm guessing they have. The rails off to the right are long gone but the rails to the left of the bridge are still there from my understanding. Im not sure why the CNW chose to leave this one up but I'm glad they did. Like I said before this thing is at least 90 years old according to this photo dated 1921..http://www.marathoncountyhistory.org/PhotoDetails.php?PhotoId=4504
I'm gonna guess the the smaller ones were taken out because of the both the facts that they were on private property and that the rails were in bad shape
Modeling the C&NW in northcentral Wisconsin, late summer 1976
Wow! What an interesting and informative exchange. RWM, MC and PN Jr are all very knowledgable. I've but out of town for a week or so or I would have chimed in earlier, but they seem to have covered all the bases pretty well.
I can attest to the relative differences from the midwest to the much drier west coast about relative bridge conditions. Had 100+ year old bridges in both places but the west coast one had virtually none of the pack rust that the midwest counterparts had.
Railroads always try to reuse bridge spans if it makes sense but sometimes the pressures of making a change out in a tight track out of service window dictate destroying the old bridge in the name of effeciency to get the new one in. It is often driven by the location and constructability issues of the site.
Have had to tell designers that while their idea for the new bridge would be lovely, it's just too bad it can't be built that way. Cities love to try to chime in on what a new bridge should look like for the beautification of their town. For the most part, railroads will tell them this is the standard bridge we build with our money. If you want something different, it's your nickle. That means you get precast concrete for up to about 30-40' spans, weathering steel deck girders for up to about 80' spans, weathering steel through plate girders for up to about 150' spans and trusses beyond that. They will all be ugly and stout as hell with no paint because railraods are not goint to set themselves up for speocal handling work in the future if they don't have to.
Paint may be needed for places such as the new lift span at Thames River but the new bascule at La Crosse is weathering steel, not to mention the difference in funding sources for each of them.
As to the last point about records....
I suspect that the FRA bridge expert who made the remark about infant mortality could also have gone on for quite a while about the importance of records. In the face of no drawings for a bridge, all you can do then is go measure everything, account for loss of section and then essentially re-create the "design" of the bridge from scratch to determine it's current rating. A lot of work and expense which shortlines, especially, are reluctant to go to. However, the FRA is going to make them start doing pretty much that.
Again, a most interesting discussion.
mudchicken(*) Hopefully not purged by the railroad operating supervision in a budget move or not handed over to a shortline during the linesale.
(*) Hopefully not purged by the railroad operating supervision in a budget move or not handed over to a shortline during the linesale.
Faint hope, that! At least in my experience. Or never handed over to the short line at all, and then lost, or whatever.
RWM
videomaker At one time there were 3 truss bridges that crossed the Brazos River at Waco,today there are 2,the Texas Electric took theirs down but the Cottn Belt left theirs,Its track gone and a Street covers the ROW on a large fill at one end..If you look at it from the ROW at the other end it looks like it goes nowhere.. ITs now a hang out for transients...The 3rd bridge is the UP-x-MKT) still active main... I know of several bridges around Tx.that are on private property since the lines were abandoned..They belong to the current land owners...
At one time there were 3 truss bridges that crossed the Brazos River at Waco,today there are 2,the Texas Electric took theirs down but the Cottn Belt left theirs,Its track gone and a Street covers the ROW on a large fill at one end..If you look at it from the ROW at the other end it looks like it goes nowhere.. ITs now a hang out for transients...The 3rd bridge is the UP-x-MKT) still active main...
I know of several bridges around Tx.that are on private property since the lines were abandoned..They belong to the current land owners...
AbandonedCotton Belt Railroad Bridge Waco,Tx.
www.flickr.com/photos/8880918@N04/3162286582/&src=1
I've been interested in Little Rock AR bridges. Still waiting for work on the Rock Island bridge to start. The Junction Bridge is now a pedestrian bridge. I can't pin down the timeline of these bridges. Did UP once own all three bridges when they were still active? I found this web site about the RI bridge.http://www.hibblenradio.com/RIBridge.html In 1989, as part of a high school research paper, I wrote to Union Pacific, which had reluctantly become owner of the bridge, which it neither needed nor wanted. Viewing it as a liability, the railroad wrote back that it would be taking down the bridge in 1991 or 92, with the lift span to be used on a bridge near Seattle, while the rest of the spans "will be removed and scrapped." Crushed that time would be running out for the bridge, which had been there since 1899 (except for the lift span, which was added in 1972), I started trespassing on the bridge, to get a good look at it. I also frequently took my camera to document the bridge before it was gone.
In 1989, as part of a high school research paper, I wrote to Union Pacific, which had reluctantly become owner of the bridge, which it neither needed nor wanted. Viewing it as a liability, the railroad wrote back that it would be taking down the bridge in 1991 or 92, with the lift span to be used on a bridge near Seattle, while the rest of the spans "will be removed and scrapped." Crushed that time would be running out for the bridge, which had been there since 1899 (except for the lift span, which was added in 1972), I started trespassing on the bridge, to get a good look at it. I also frequently took my camera to document the bridge before it was gone.
Murphy Siding RWM and PN Jr: Thanks for the info. For some reason, I do find things like this interesting. I do, however, have a hard time getting my mind around the idea of re-engineering a 100+ year old bridge. It just seems there would be a lot of unknowns about the stength qualities of material that old. Having the old plans and specs would sure be an asset. I'm sure railroads are good about saving important things like that. What about in my area? There are lots of small bridges built out of big cresote timbers. Those, I could visualize being fairly easy to re-calculate. Even more exciting, there are lots of smallish bridges built out of pink Sioux Quartzite and masonry cement. Where would an engineer start with one of those?
RWM and PN Jr: Thanks for the info. For some reason, I do find things like this interesting. I do, however, have a hard time getting my mind around the idea of re-engineering a 100+ year old bridge. It just seems there would be a lot of unknowns about the stength qualities of material that old. Having the old plans and specs would sure be an asset. I'm sure railroads are good about saving important things like that.
What about in my area? There are lots of small bridges built out of big cresote timbers. Those, I could visualize being fairly easy to re-calculate. Even more exciting, there are lots of smallish bridges built out of pink Sioux Quartzite and masonry cement. Where would an engineer start with one of those?
Timber Pile Trestles will last longer in a drier climate (if you don't do regular maintenance & Inspect - that statement goes in reverse -!) ... the ones with t-rail stiffening become a more subjective discussion of how they help or hurt everything from the stringers up.
That Engineer you are asking about starts by getting out the old high tech ball-pein hammer and his calibrated ears looking for punky wood and spalling rock/concrete. Then you hope he has old bridge files(*) and other history of the bridge.
(*) Hopefully not purged by the railroad operating stupervision in a budget move or not handed over to a shortline during the linesale.
Thanks to Chris / CopCarSS for my avatar.
Railway Man I haven't been to that particular bridge in about 10 years, but I don't recall seeing anything on site that made me think then that anything had been done other than tie replacement, ever. In most cases of bridges of that nature, to my knowledge nothing has been done absent a specific injury or failure. [snip] RWM
Oh yeah, that's the original thing, all right - it could have been in a museum !
I looked at Chad Thomas' photo of it over on the other thread earlier today - here's what I noted briefly: paired "eye-bar" main tension diagonal members (which are inherently self-limiting to tension [only] for both analytical and functional reasons, because if any compression is applied they merely bow out rather than bear any of that kind of load), with real pins at each connection, single-bar "counter" ties with a built-in clevis-type deflection adjustment, built-up lattice-work vertical compression members, heavy/ large top compression members and portal end posts, thin bottom tension bars in the middle, lacy top sway, portal, and lateral (wind) cross-bracing, etc.
Finally, I had a chance to think about something related to this over lunch that hasn't been mentioned so far, and thought I'd run it by you, with your extensive experience out that way (which I don't have):
Does the desert - or at least much drier - environment prevalent over so much of the Western U.S. (as contrasted with the East and South) reduce the environmentally-driven corrosion and deterioration, and hence contribute to the longevity of such structures, esp. those with as much fine detail and steelwork as this one ?
I'm hard-pressed to think of any equivalent mainline structures still in use here in the Eastern U.S. with as many small pieces and connections. Pretty much everything of that sort has been replaced by simpler, more massive structures with "cleaner" lines that have far less numerous connections and angles to catch dust, debris, water, and then rust out, etc. With 50+ inches of rainfall here in eastern Pennsylvania this year - only about 20% more than normal, though - I can't imagine this structure would have survived unaltered for so long. Either the B&B forces would have gotten tired of - or more honestly, the budgets would not have supported - frequent cleaning and repainting, or else components would have needed replacement by now.
Any thoughts, pro or con ? Thanks.
Murphy SidingRailway Man Most of the main line bridges in the West from that era that I've dealt with are E-72, when re-rated. Some are E-80. Branch line steel bridges in the West from that era I've dealt with are usually E-60, assuming no significant loss from corrosion. RWM Why, and how, would bridges be re-rated for loading capacity?
Railway Man Most of the main line bridges in the West from that era that I've dealt with are E-72, when re-rated. Some are E-80. Branch line steel bridges in the West from that era I've dealt with are usually E-60, assuming no significant loss from corrosion. RWM
Most of the main line bridges in the West from that era that I've dealt with are E-72, when re-rated. Some are E-80. Branch line steel bridges in the West from that era I've dealt with are usually E-60, assuming no significant loss from corrosion.
Why -- because the railroad wants to know not just the strength of the bridge, but whether the loadings it intends to place on the bridge will accelerate its deterioration and change its life expectancy. It also wants to know if corrosion or other deterioration has affected the load rating or lifetime of the bridge. Often corrosion has had its greatest effect on minor members and is not significant.
How -- the engineer inspects the bridge. Inspection methods include visual observation for cracks, sheared rivets, distorted or deflected members, and frozen joints. Simple additional methods include measurements of member thickness to determine how much has been lost to corrosion. More elaborate and expensive methods include magnetic particle testing, dye testing, ultrasonic testing, and x-ray. Following the field inspection, the engineer uses the original drawings (if available) to calculate a load rating using member properties adjusted for thickness loss (if any) and other field inspection results, using the desired Cooper live-load rating.
Read this if you really want to know more (it's for highway bridges but the testing methods are similar):
http://www.ndt.net/article/ndtce03/papers/v109/v109.htm
Edit -- ah, Paul beat me to it with more and better detail. I got delayed trying to decide if I wanted to explain what finite element analysis is, and people sticking their head in the door, etc.
Murphy Siding Railway Man Most of the main line bridges in the West from that era that I've dealt with are E-72, when re-rated. Some are E-80. Branch line steel bridges in the West from that era I've dealt with are usually E-60, assuming no significant loss from corrosion. RWM Why, and how, would bridges be re-rated for loading capacity?
An astute question - got you wondering how something more can be created without adding anything, I'll betcha ? Well, here goes:
(1) As part of routine regular inspections and analysis/ evaluation/ "investigation" - a term of art for this kind of review. It answers: "Is this bridge still good for carrying its design or rated loads, and the trains that we're running over it now ?"
(2) As part of a special inspection/ analysis/ evaluation/ investigation, which could be triggered by any of:
(a) Proposed new loads - such as the increases from 263K to 286K and proposed to 315K gross wt. cars. Back in the steam loco days, a new class of loco (= heavier) would also trigger this. In diesel days, probably the heavier ballasted SD-series did too - their individual axle weights weren't all that greater thatn 4-axle units, but 50% more in the short wheelbase of a truck would be a concern and need to be investigated;
(b) Concerns over inherent weaknesses and vulnerabilities of a particular design, often certain specific details of the connections. Recall that after last year's collapse of the Minnesota bridge, there was a flurry of inspections of similar-design bridges. Simialrly, about 25 years ago there was a rash of "lamellar tears" of welds into large steel members - as Ed King recounted in one of his articles, I believe one of them was caught by a Rock Island RR bridge engineer in the CTA bridge over his commuter train line on a cold winter morning. Related to this are those deisgns and details that are susceptible of "fatigue", which is a progressive weakening or loss of ductility caused by and after many repetitive loading cycles, aggravated by stress reversals (from copression to tension and back again), and frequent loads near the component's maximum rated load;
(c) Whenever something out-of-the ordinary occurs of the "uh-oh" nature that would cause a reasonably prudent bridge engineer or inspector (= obsessively cautious, in my experience - which is praise, not a criticism) to question the continuing validity or suitability of the existing rating - such as an uncommonly high amount of corrosion is discovered, some pieces fall off, it gets hit by a truck or barge or a shifted load, scour or washouts under a pier, fire damage from below or above, termites in the case of a wood bridge, spalling and deterioration in the case of a concrete bridge, doubts about a specific metallurgy - cast iron has long been obsolete, excessive vibration or deflections from wind (think of the 1940's wildly swaying suspension bridge - "Galloping Gertie" bridge over Puget Sound, I think it was ?) or other causes, etc., etc.;
(d) In this instance, it probably occurred more in the nature of a long-term capital planning study of the nature, "Can we continue to use this bridge for our new modern trains - is it still good for that ?"
When that occurs, the bridge should be the subject of a thorough inspection and study. Very briefly - and greatly simplified, all the members are examined for corrosion, cracks, looseness, bends, signs of distress, and other defects; connections are checked for same, plus loose or missing bolts or rivets, etc., both visually and by ultrasound/ magn-flux/ radiograph, etc.; piers and substructure are evaluated for soundness and good bearing; the deck under the track is likewise checked. Notably, specimens of the steel or concrete or sometimes even a whole member will be removed and tested for its chemistry/ metallurgy, ductility/ impact resistance, esp. in cold weather, and so on. At the end of that process, an engineering judgment is made as to the capability of each of the members to carry certain stress levels. Next, the structural engineers calculate the maximum load that the bridge could carry, based on the allowable stresses in each of the several classes of members. Frequently the new allowable load is safely greater than that of the original design, because of the conservatism of the original engineers and builders - the members are often bigger than they really needed to be - and a much better understanding today of the metallurgy and the structural engineering and dynamic aspects of how each member and the structure as a whole responds to imposed loads and stresses. Not to be overlooked in this regard are the dramatic improvements in the mathematical analysis and calculations made possible by the current computer programs. Aspects that were over-sized or were based on safe assumptions can now be examined and tested much more criticially, which often - but not always - reveals that there is quite a bit of reserve capacity, even allowing for corrosion, old metals, etc., etc. What our forebears had to do by general rules of thumb and based on experience (only) can now be analyzed in minute detail.
Finally, a minor but nevertheless real consideration is that the stronger and stiffer rails and track structure, and the "internal bridge" of the longer frames of modern locomotives and most railcars (except iron ore "jennies" !) spread and carry the loads out over longer portions of the bridge than in the old days, when a steam loco had many heavily loaded wheels spaced close together. For example, a Union Pacific Big Boy was what ? - 1 or 1.25 million pounds = 500 to 625 tons ? - on almost a centipede's worth of wheels continuously over it's entire 135 ft. (approx.) wheelbase. In contrast, only 2 modern diesels - each about 70 ft. long - will fit into that same length, and at about 200 tons each or 400 tons total. Plus, half of those 2 diesels' wheels and weight are at the outer ends of that length - so only half of the weight is near the middle, with nothing near the "quarter points" - only the air above the rails. This aspect can cut both ways depending on the configuration of the structure - and technically isn't applicable or relevant if the analysis is being done in strict accordance with the patterns of Cooper's bridge loadings and formulas,as opposed to one of the more modern loading patterns (such as the late Dr. Steinman's), but hopefully you get the idea.
Hopefully this starts to answer your questions. I'm sure I left out or simplified a lot, but other forum members will feel free to fill in those gaps. I've got to run to lunch now.
Railway Man I haven't been to that particular bridge in about 10 years, but I don't recall seeing anything on site that made me think then that anything had been done other than tie replacement, ever. In most cases of bridges of that nature, to my knowledge nothing has been done absent a specific injury or failure. The most common repair or improvement is to piers or abutments following a scouring event or subgrade setllement, but not to the steel span itself. Most of the main line bridges in the West from that era that I've dealt with are E-72, when re-rated. Some are E-80. Branch line steel bridges in the West from that era I've dealt with are usually E-60, assuming no significant loss from corrosion. RWM
Thanks ! Just exactly the insight I was hoping for - but not realistically expecting anyone to be able to provide. It speaks eloquently to this subject - a 102-year bridge, still going strong in the same condition it was built in ("consumables" excepted, of course, as you noted), up until a few days ago. Much appreciated !
Have a good New Year - both the Day itself, and the rest of the year, too !
Paul_D_North_Jr One thing I'm curious about, though it'll probably be tough to find an authoritative answer: How much of that bridge was still "original" from its circa 1906 construction ? (I'm thinking of the old joke about the French Canadian woodsman's axe - "Yah, I've replaced the handle 6 times and the head twice, but she's still the same old axe !") The reason I ask is that back then (1906), the typical "Cooper's loading" for railroad bridges probably would have been not more than the E-55 to E-60 range (per WIlliam D. Middleton in his book Landmarks on the Iron Road: Two Centuries of North AMerican Railroad Engineering, Indiana University Press 1999, ISBN 0-253-3559-0, pg. 9). Since today's design loading's for steel bridges are in the E-80 range, it is possible that the 1906 bridge had to be upgraded over the years to handle heavier modern trains. On the other hand, back then such things were often conservatively designed and built = excess capacity. The modern standard is not that much higher, so the 1906 bridge may have been OK to continue using with either none or only a few upgrades and replacements of selected components.
One thing I'm curious about, though it'll probably be tough to find an authoritative answer: How much of that bridge was still "original" from its circa 1906 construction ? (I'm thinking of the old joke about the French Canadian woodsman's axe - "Yah, I've replaced the handle 6 times and the head twice, but she's still the same old axe !")
The reason I ask is that back then (1906), the typical "Cooper's loading" for railroad bridges probably would have been not more than the E-55 to E-60 range (per WIlliam D. Middleton in his book Landmarks on the Iron Road: Two Centuries of North AMerican Railroad Engineering, Indiana University Press 1999, ISBN 0-253-3559-0, pg. 9). Since today's design loading's for steel bridges are in the E-80 range, it is possible that the 1906 bridge had to be upgraded over the years to handle heavier modern trains. On the other hand, back then such things were often conservatively designed and built = excess capacity. The modern standard is not that much higher, so the 1906 bridge may have been OK to continue using with either none or only a few upgrades and replacements of selected components.
I haven't been to that particular bridge in about 10 years, but I don't recall seeing anything on site that made me think then that anything had been done other than tie replacement, ever. In most cases of bridges of that nature, to my knowledge nothing has been done absent a specific injury or failure. The most common repair or improvement is to piers or abutments following a scouring event or subgrade setllement, but not to the steel span itself.
OK, I think I now "get it" - erikem's point regarding the Carlin, NV bridge. At the risk of "putting words into your mouth", what I'm "taking away" is that as just one handy example, it was only 102 years old - to which the 40-year old Minnesota bridge was indeed a comparative infant (or mayber teenager). Also, that "but for" the happenstance of that career-ending derailment, the bridge may well have continued to be in regular service for many more years.
One of the more challenging tasks for the "B & B" crews ("Bridges & Buildings") is to replace / renew / upgrade individual structural components in an existing structure, between trains, but it can be and is done. And so I'm wondering if and to what extent that was done to this bridge ? Just food for thought.
mudchickenThe bridge at Carlin, NV would still be there if the derailed train had not struck it. (Kind of a problem with large span thru-truss structures, they tend to not to not be redundant - take out one member and the whole thing goes like a house of cards)
The bridge at Carlin, NV would still be there if the derailed train had not struck it. (Kind of a problem with large span thru-truss structures, they tend to not to not be redundant - take out one member and the whole thing goes like a house of cards)
Which gets back to the FRA guy's comment about a forty year old bridge collapsing being considered "infant mortality". Age would have been a cause for blame if the bridge near Carlin collapsed under normal traffic - I figured that the collapse was related to the derailment (and probably should have been more explicit about it).
My other point was that there is nothing magical about RR bridges other than having to be built stoutly to maintain sufficient rigidity for handling RR traffic.
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