2015 the UPRR replaced the old Iron Truss Bridges where the North Fork Branch crosses the Gunnison River in Delta County Colorado. Sad to see the old bridge go, but if there were a failure as a train was crossing the bridge, the cost of a new bridge probably worth the cost. UPRR made the decision as coal traffic on the North Fork Branch has dropped. We have gone from 3 active mines to 1 in the past few years.
Here are the 3 Truss Spans before construction started. January 2015
Construction was done in 2 segments. Here the East Span has been replaced. Next 3 pictures taken October 08, 2015
Here is the scrap pile of the demolished Truss. The trackhoe on the right has the large Jaws for cutting up the scrap iron.
Next 3 pictures taken October 16, 2015
Crane on site ready for replacement of the 2 West Truss spans. Dec 05, 2015
Note the new concrete piers under the old Steel Truss. Dec 05, 2015
Here the middle Truss has been lifted off and placed on the ground. The next 5 pictures taken December 08, 2015
Here the West Truss is being lifted up by the crane.
Note the new bridge sections on the ground.
Next Day December 09 2015, a Coal Train crossing the new bridge.
The remains of the Old Truss ready to be cut up for scrap.
Finished Bridge October 2016
Steve
Nice story and great photo series.
For those of us who are railroading engineering types (Mudchicken and Paul North are you also out there?) this is a wonderful sequence of photos with much to note.
My observations:
Old piers were not reused. Looking at the size of them, and the age of the truss spans, I wonder if that was concrete jacketing around original stone piers. Probably has much to do with use of new piers. Also, the foundation of those old piers may have been suspect or worse (scouring or deterioration of wood grillage and piling may be involved). When seeing stout stone or concrete piers it's hard to believe that many of those piers are just sitting on a wood platform (grillage) supported by wood piles.
Steel spans may be reused from another location as they look dark (painted black?). The railings don't match the railings on the concrete approach spans which also suggests reused spans.
New spans are much shorter necessitating several piers in stream bed (four vs. two originally). UP obviously not worried about piers being washed out, unlike old days. Railroads used to avoid placing piers in water if possible and would use longer spans to do so.
Note use of UP-standard short-span pre-cast concrete bridge sections on both approaches, and steel H-pile bents instead of concrete piers where no water is normally flowing. Also note the different bent construction with two H-piles on end of each bent instead of normal four or five piles spaced along bent. I have not seen (or at least noticed) this type of bent construction before.
Ballasted deck across new bridge to make the track forces happy. Can replace track ties with normal tie gang instead of having B&B replace bridge ties (much easier). Easier to surface and smoother riding also. When ballasting track there is no need to have B&B raise bridge spans to match new (higher) track level. If spans are not raised it creates a hole or dip at bridge that creates problems.
Those old truss spans did have a more "railroady" look but they also looked on the lightweight side to me so they may have been questionable for today's loadings. Wonder what the Cooper's rating was on the old spans? May have been corrosion or fatigue damage also. The new bridge will probably outlast the railroad given the decline in coal traffic in the last few years.
Steve, thanks for the posting the photos.
Kurt Hayek
Its amazing how quickly the old bridge piers were removed.
"It's amazing how quickly the old bridge piers were removed."
Looking at the dates I saw the old pier for the east span (removed earlier) and the east end of the center span was still there on Dec. 5; it was completely gone by Dec. 8 (the next photo sequence). The pier for the west end of the center span and the west span was still there sometime on Dec. 8 but was at least partially gone by the next day when the new spans were set. A hydraulic excavator with impact breaker would make short work of those piers (and I spotted two excavators in the photos), especially if they were concrete-jacketed stone piers as I speculated previously.
The low level of rail traffic helps a lot on a project like this as there is plenty of uninterupted track time available. Note also how the river was partially filled in making it easier to get heavy machinery to the bridge.
I noticed that the the picture date of the start of replacing the last 2 spans was just days after Arch Coal (the owner of the West Elk Mine, the last one on this branch line) emerged frpm bankruptcy.
http://www.denverpost.com/2016/10/05/arch-coal-west-elk-mine-colorado-bankruptcy/
MidlandMike I noticed that the the picture date of the start of replacing the last 2 spans was just days after Arch Coal (the owner of the West Elk Mine, the last one on this branch line) emerged frpm bankruptcy. http://www.denverpost.com/2016/10/05/arch-coal-west-elk-mine-colorado-bankruptcy/
Arch Coal, The West Elk Mine is the last working mine in the valley. The Bowie Mine still has some coal in their stockpile to ship but maybe only 5 more trains.
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