I thought there might be interest in this South Shore bridge replacement over Torrence Avenue, Chicago and the NS (former NKP) Fort Wayne Div.
Rather cool time lapse video on YouTube, showing them putting in the bridge.
http://www.youtube.com/watch?v=yx0-MXI-U5Q&feature=youtu.be
Bill Vandervoort, Chicago, IL
Neat! Thanks for posting the link!
Begs the question of where the bridge span was actually constructed so that it could be rolled into place as it was.
Since I grew up about two blocks from where the bridge was installed, let me describe similar situations. When South Shore replaced its Calumet River bridge, the bridge was built on a barge adjacent to the right-of-way and was floated into place. When N&W replaced the former NKP Calumet River swing bridge with a vertical lift bridge, the lift span was also built about a mile downstream and floated into place between the towers. I would assume that gravel roadways were laid out and the new bridge over Torrence Avenue was rolled into place from a nearby site, probably immediately west of Torrence Avenue and south of the South Shore main line.
If I understand the article correctly, the next step will be to run the street beneath the NS line? I assume that will change the road alignment, since tat appears to be one big bridge to replace what looks to be a relatively short span.
Kevin, if you look at the beginning of this (amazing–thanks!) video, there are two spans on the existing South Shore line; they’re linked by a trestle, if I recall correctly (it’s been a long time since I’ve been down that way, since there are easier ways to get to Dolton from anywhere).
If they put Torrance under the NS tracks, they’ll almost certainly have to put 130th under the tracks as well. This has to be a busy grade crossing, with the Ford plant very close by.
I rode the South Shore about a month ago and saw the construction site. Now I know what was going on. Love the video.
That was impressive…! Thanks for sharing. That bridge appeared to be well made for heavy duty use…and a right lengthy span. I wonder just how many tons that structure weighs…?
The short span they had the vertical supports installed was surprising. Not very far apart. And how was the frame structure made on that wheeled power unit…Didn’t seem like very much room to have heavy steel in such a frame to handle THAT kind of weight. But it sure seemed to work like clock work.
Wonder how much the center settled when the bridge finally settled on it’s end abutments…?
6:18 AM to 4:31 PM according to the counter at the bottom = 10 hrs. 13 mins. = 613 mins., condensed down to 4 min. 57 secs., or about 120:1 speed-up/ compression.
How many ‘cherry-pickers’ / ‘man-lifts’ were in use altogether ? The rental company must have been thrilled to snag this account !
Notice the group of officials/ “sidewalk superintendents” watching in the foreground early on, then later from the bridge itself.
I really liked the intense activity with the mast signal in the foreround - put it up, take it down for the bridge on the rubber-tire transporter dollies to pass by close overhead, then put it back up again later !
Thanks for sharing !
Thoroughly cool. Thanks for posting. When does the South Shore commence service over the bridge?
What is the function of the risers along the top of the bridge on both sides ?
Quentin, I suspect that the bridge was built on risers or in a place that could be dug out so the dollies could be positioned underneath, rather than on the dollies.
I also suspect that there wasn’t much settling at this point. It might be noticeable when rails, ties, and ballast are laid (I’m assuming that this will be a ballasted-deck bridge, as nearly everything is nowadays).
Mike, are you referring to the catwalk along the south side of the bridge about halfway up? I suspect that it will have something to do with the electric catenary.
Carl…I just pulled the video up again, and see what I missed the first time. I didn’t notice there were TWO powered wheeled platforms…or whatever the correct name for them are. I thought I saw just the ONE platform in the first look, and wondered how that piece of equipment could hold so much weight…and balance the bridge as it was moving into place. So my second look answered my question.
As for how it was built…That would not have been any great problem to build the bridge in an elevation suitable to place the “carriers” under it when it was ready to move. Another thing I watched…was how close in elevation they had it figured when the moved it in place…Didn’t seem like there was very much clearance from the bridge mountin /supporting plates to the abutments…Overall, it certainly looked like a real professonal piece of work…
Probably to support or attach safety lines to when inspecting or working on (painting) the bridge in future years. The catwalk in the middle height of the bridge is likely for the same purpose.
These kinds of appurtenances were unknown in the old days, but with the modern emphasis on safety, are becoming more prevalent, and are now designed and installed from the get-go. It’s faster and cheaper in the long run than having to re-rig them every couple of years for such work. I’ve seen similar setups for workers at facilities that unload tank cars and covered hoppers, measure and tie-down excess dimensional - “high & wide” - railcar loads on the PB&NE, and “Repair-In-Place” (RIP) tracks at the local NS yard.
I was referring to the rods sticking above the top-most structural member on both sides of the bridge. When you mentioned the catwalk, I noticed the riser rods were about the same size as the catwalk handrail stanchions. Maybe the mystery rods are stanchions for a cable handrail along the top.
PS. Paul, I saw your post after I posted this. I think we were thinking the same thing.
Thanks for sharing … we have watched it several times and catch something new each time.
Our favorite is the man in the lower left corner who is keeping the stack of railroad ties from blowing away by sitting on them. 
[(-D] [tup]