This site has a daily aerial overhead sequence showing progress of the reconstruction.
It appears they have done some pile driving. There is a large sandbar that has developed upriver from the bridge site with half of the river channel blocked by construction berms.
https://storymaps.arcgis.com/stories/39cfab281e6f4df08311b7e59a3b811a#n-MIhBCH
Thanks for updating the photographs. Amazing what has been done so quickly.
As of July 15 the west span has been dragged out of view.
It looks like a large ramp has been built from the south to reach what looks to be where the intent is to build a new pier.
I wonder what the flow rate of the water is through that portion of the river with approximately half of it effectively dammed up?
Also, reflecting on the whole situation, that bridge likely handled the weight of Northern Pacific Z-7 and Z-8 4-6-6-4 Challengers back in the day that tipped the scales at 1,081,000 lbs. It was a substantial structure.
Between July 11, 12, 13 they scrapped the western span on site. You can see it from the daily ARCgis photos.
As of July 15 they have pushed out the working berm to encompass what looks to be an area where they are intending to put a new bridge pier or new supports of some type.
On July 16 on the very left side of the ARCgis view, what looks like a new bridge pier supported by 8 pilings appears.
Then what looks like a sectional bridge deck appears.
Then another bridge pier supported by 8 pilings appears, then another sectional bridge deck.
It may be that they are using construction similar to the new bridge across Lake Pend Oreille.
kgbw49 On July 16 on the very left side of the ARCgis view, what looks like a new bridge pier supported by 8 pilings appears. Then what looks like a sectional bridge deck appears. Then another bridge pier supported by 8 pilings appears, then another sectional bridge deck. It may be that they are using construction similar to the new bridge across Lake Pend Oreille. https://storymaps.arcgis.com/stories/39cfab281e6f4df08311b7e59a3b811a#n-MIhBCH
(6 piles per pier, actually. I think the eight things you're seeing in the July 16th photo are bearings on the top of the pile cap for the four-girder spans that will be set on it.)
The technique used for maybe 90% of all railroad bridge replacements is:
1.) Drive, vibrate, or drill piles into the ground.
2.) Weld a precast pile cap on top and some cross-bracing between them
3.) Set simply-supported precast or prefab spans on the pile caps. For a short ballast-deck span, the girder is just a concrete box girder and the ballast sits on top. For an open-deck bridge, the prefab span consists of just the beams or girders, bracing, and diaphragms. For a steel ballast-deck bridge, the prefab span is similar to an open-deck span but with a steel "pan" welded on top to hold the ballast. In some cases, the span is actually delivered in two pieces with a seam running down the middle of the track just to keep dimensions and weights manageable, and a minimal amount of assembly may be required once it's set in place.
4.) Build the track and run trains.
The reason why this technique is used in most cases is because it allows you to do the slow, difficult business of installing piling without removing the track. When the time comes to install the superstructure, you have to take the track out of service, so you want as much work as possible to already be done.
The same technique works well for replacing a lost bridge. The first thing you do is try to collect as many already-built pieces as possible from emergency stock, other projects in progress, etc. The second thing is get these pieces coming and start doing any necessary pre-casting or pre-fabrication of new pieces WHILE the tedious pile installation is underway. Once the pile is in, hopefully the caps and spans are ready to set in place.
The new Lake Pend Oreille bridge in Sandpoint was built a little different. It was built off-line, meaning impacts to train traffic weren't as critical. You don't have to be able to pre-assemble everything, which means you can use longer spans with deeper, heavier girders. You're more free to pick a span length that provides an economical balance between superstructure cost and pier construction cost. In particular the new bridge at Sandpoint was built by setting individual pre-cast girders into place and then pouring a concrete ballast deck on top.
Back to the MRL: there are a lot more details I can't share that I'm sure will eventually come out in an AREMA presentation, but you've already pieced together most of it just from those drone photos .
Dan
(Speaking only for myself and not representing BNSF.)
dpeltier, thank you so much for sharing your knowledge! It is fascinating to know all those details. Much appreciated! I oversee a bit of building construction in my day job and I am always impressed by our engineers. It certainly seems from progress so far that MRL is going to meet their goal of the bridge replacement lasting weeks instead of months. Thank you again!
Looks like they are within two spans of connecting to the eastern truss span of the original bridge. (It looks to be a Warren truss with verticals.) As of 07/19 track has been laid on the new spans.
As of July 20 it looks like all the pilings have been driven and the last new spans will be placed soon, if they are not placed already.
There is also ballast on several of the new bridge spans on the west side of the bridge.
July 21 - Whoomp! There it is!
https://storymaps.arcgis.com/stories/39cfab281e6f4df08311b7e59a3b811a
There looks to be a Brandt truck on the eastern surviving truss span, and maintenance of way equipment on the track just to the west of the new spans.
Great work. Appears that the temporary berm in the river is alredy partially removed on the up sream side of the bridge. 26 - 27days for restored service maybe another week to clean up? Dredge work mostly.
Stillwater Train Derailment (arcgis.com)
Looks like they are starting to disassemble the ginormous crane.
Now what is the cause of the collaspe? So far 3 have been put forward. Maybe more? Underscoring of the sup4ort of the bridge.? Lading or a car(s) snaging the bridge.?
Question. Will BNSF do something to the old remaining column to prevent any underscoring that is evident in the area of the bridge?
tree68 Inasmuch as the railroad will be repairing their own property, not building new, I suspect permitting would be minimal, unless there is something particularly sensitive, environment-wise, involved. Because the railroad is a private entity, it can do pretty much what it wants in terms of labor and materials. While union rates do figure in, they won't be as cumbersome as the statutory requirements faced by government entities, where there are bidding requirements, etc. While government agencies tediously assemble requirements in preparation for requesting bids, the railroad will be hauling the materiel it needs from stock or from established vendors. Kinda like painting your house - you decide what color you want, maybe hire a couple of local kids (or a handyman or even a painting company) to help you out, and paint away. If it was a municipal building, odds are it would all have to go out to bid, meaning the bid specs have to be developed, perhaps a request for proposals put out, bids requested, opened, etc. You're sitting in your nicely painted house, the municipal property will get painted next year. Unless someone doesn't like the color and sues...
Inasmuch as the railroad will be repairing their own property, not building new, I suspect permitting would be minimal, unless there is something particularly sensitive, environment-wise, involved.
Because the railroad is a private entity, it can do pretty much what it wants in terms of labor and materials. While union rates do figure in, they won't be as cumbersome as the statutory requirements faced by government entities, where there are bidding requirements, etc.
While government agencies tediously assemble requirements in preparation for requesting bids, the railroad will be hauling the materiel it needs from stock or from established vendors.
Kinda like painting your house - you decide what color you want, maybe hire a couple of local kids (or a handyman or even a painting company) to help you out, and paint away.
If it was a municipal building, odds are it would all have to go out to bid, meaning the bid specs have to be developed, perhaps a request for proposals put out, bids requested, opened, etc. You're sitting in your nicely painted house, the municipal property will get painted next year. Unless someone doesn't like the color and sues...
Nice job of summing up the process. Sometimes for a large construction project there are years of trying to get funding and designing the project involved and putting together specifications before it's ready for the procurement process. I spent 30 years advertising, awarding and administering Federal contracts. Even with all the work that goes into such a project, every crank who never built anything in his life thinks he/she knows a better way to do it, too.
blue streak 1 Stillwater Train Derailment (arcgis.com)
Our community is FREE to join. To participate you must either login or register for an account.