Re: Bridge girder on three PRR FM flat cars
Guy Wilber
mel perry wrote:
“that also my thought, there is no forward or backwards restrains at all, i guess back then "g's" hadn't been invented, lol” The load matches The ARA’s Open Top diagram (for the period) for girders. The manufactured bolsters are bolted to the flat car deck through its ends and on each side of the center sill. The girder is secured on each end with the rods passing through the attached bolster and into the bracket bolted to the bottom flange. Guy Wilber Reno, Nevada
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Re: Bridge girder on three PRR FM flat cars
Matthew Metoyer
These Erie photos tend to be of damages, either to the car or lading. Could the load have shifted and hence the photo? Matthew Metoyer
On Sat, Dec 21, 2019 at 3:01 PM mel perry <clipper841@...> wrote:
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Re: Bridge girder on three PRR FM flat cars
mel perry
that also my thought, there is no forward or backwards restrains at all, i guess back then "g's" hadn't been invented, lol :-) mel perry
On Sat, Dec 21, 2019, 12:32 PM Charlie Vlk <cvlk@...> wrote:
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Re: Bridge girder on three PRR FM flat cars
Charlie Vlk
Llyod
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Think about the dynamics of the three cars going over the approach and crest of the hump.....the load is not secured for extreme vertical curves nor the impact of running into a string of cars after being humped (if the middle car didn’t dislodge the girder as it went over the top!!). Charlie Vlk
On Dec 21, 2019, at 10:57 AM, Charles Peck <lnnrr152@...> wrote:
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Re: Bridge girder on three PRR FM flat cars
Tony Thompson
Not that the load rests on both end flat cars between 4 and 5 stake pockets from the end. As Bruce Smith mentioned, this is doubtless the preferred loading point. Tony Thompson
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Re: Bridge girder on three PRR FM flat cars
I think he was referring to the fact that the load is all the way left on the nearest car, and not centered on the center car.
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Thanks! Brian Ehni (Sent from my iPhone)
On Dec 21, 2019, at 12:24 PM, Drew Bunn <drew.r.bunn@...> wrote:
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Re: Bridge girder on three PRR FM flat cars
Drew,
He meant end to end, not side to side 😉 and the load is definitely offset to the near end of each of the end cars. That is for good reason. The location of this load is due to several factors:
1) Most flat cars CANNOT carry their rated load concentrated at the center of their span. Offsetting the load to one end or the other allows a heavier load to be carried. In the PRR fleet, the F22 and F23 were among the only cars that could carry their rated
weight in the center of the span of the car.
2) There were limits for the allowed free span between the pivot points. Too long a span would overhang on curves and could exceed line side clearances. Think about 85' passenger cars on 18" HO scale radii 😉
3) There were also limits for the free end length for the same reasons as #2, although that was less likely to be an issue
Removal of the brake wheel was no big deal... done all the time.
While hump yards were at least 25 years old at the time, they were not common. Looking at this load, I see a card on the side of the 3rd flat. While this is most likely a route card, it may also contain the instructions "Do Not Hump". Alternatively, rules are
made because of stupid people. At this point in time, that rule may yet to be in effect as everyone looks at this load and KNOWS it should not go over the hump. Give stupid folks a few more years to screw it up and the sign will be required.
Regards,
Bruce Smith
Auburn, AL
From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> on behalf of Drew Bunn <drew.r.bunn@...>
Sent: Saturday, December 21, 2019 12:24 PM To: main@realstmfc.groups.io <main@realstmfc.groups.io> Subject: Re: [RealSTMFC] Bridge girder on three PRR FM flat cars Not to sound insulting, Claus - but I think you're seeing things. There is no way that load would remain upright unless it was perfectly centered on those flats. I've unloaded centerbeams, and two forklift operators have to remove the load evenly on both
sides or the car will fall over.
Cheers
On Sat., Dec. 21, 2019, 10:21 Claus Schlund \(HGM\), <claus@...> wrote:
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Re: Bridge girder on three PRR FM flat cars
Claus Schlund \(HGM\)
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Hi Bil and List Members,
Interesting insights there Bill!
From the flat car's point of view, this would
appear like it is a point load, since the flat carries the full load at
the spot where the load bolsters (is there a more correct term for this?)
are installed on the flat. Puting the point load right in the middle of the car
would make the load stress the worst it could possibly be, and moving it closer
to the trucks would help with this.
Claus Schlund
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Re: Bridge girder on three PRR FM flat cars
Claus Schlund \(HGM\)
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Hi Drew,
No insult taken, but perhaps I was unclear in my
question...
I meant to say it was not centered across THE LONG
WAY. Indeed, I feel as you do, that it is properly centered across the
short way
On the flat car closest to the camera, the load
comes to nearly the end sill of the car. On the flat car furthest from the
camera, the load comes to only about the middle of the car. If centered the long
way, both flats would have the load end at roughly the same place
on both cars.
Claus Schlund
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Re: Bridge girder on three PRR FM flat cars
Bill Keene
OK. Here is my take on why the girder was not mounted to pivot on the longitudinal center of the end flat cars…
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Placing the pivot point closer to the truck would result in less overhang inward on curves. Also doing so may reduce the outward overhang at the ends of the girder. In short, there may have been operational restrictive reasons for what appears to perhaps be an odd loading. Also, a long shot idea here, loading closer to the trucks would perhaps allow for a heavier load to be carried than what would be the limit if loaded at the longitudinal center of the car. Both of the above are just food for thought. Cheers, Bill Keene Irvine, CA
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Re: 3D printing (Was: New early P&R steel.....)
I would like to offer to shed some light on the Jet printing Process, as it seams there is a genuine interest by this group to further understand the process. At work I manage and run both a 3D Systems Projet 3600 and Projet 5500 printers. These are what are know as ‘Polyjet' or ‘Multijet' 3d printers and is what Shapeways uses for their Fine Detail processes. The 3600 has a build area of about 8" x 12” inches and the 5500 16” x 20”.
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The print head on these printers has two rows of jets, one for the model or body material as Tom called it and another for the wax or support material. The print head on the Projet 5500 has 2400 jets across a width of 8”. This works out to 300DPI. To achieve higher resolution the print head shifts sideways by a pixel width and makes two passes for each layer to achieve 600DPI. For 750DPI it makes three passes for each layer and shifts both left and right of the first pass by 0.66 of a pixel width. I may have the math wrong for 750 DPI but I hope you get the idea. After each layer is deposited at what ever DPI selected, the head has a spinning roller that pushes or forces the deposited resin down into the previous layer. Behind the roller is a knife blade that slices the resin layer to the choose layer thickness. The final step is the head has a UV light that turns on and cures the layer. The 5500 head is only half the width of the build plate and must make a shift half the build plate width to print the entire 16” width. The 3600 print head is the full width of the build plate. Part print orientation is critical to get better printed parts. The head moves in the x axis. Thus if you want to orient your part along or across the print direction you need to pick which side of your part aligns with the X axis in your CAD file. I always design models as flat kits with the show side facing up on the build plate so no wax is used to support the critical faces of the part. To answer an earlier question as to the rigidity of these machines. They are built like machine tools. They have heavy frames, use servo motors(not stepper motors) and linear guide way bearings just like the CNC mills we have at work also. The Projet 5500 weighs in at 3000lbs. As far as process control. There really isn’t any. You load the part into the software, Orient it the way you want and press the print button. The only human involvement is the support removal. The wax is melted off in an oven, and then the last of it is removed in an ultrasonic cleaner. The big issue is warpage caused when the part is in the oven. I no longer remove wax for model parts in the oven. I remove it with a hobby knife and a dissolve the last of it with alcohol. Thus avoiding warpage. Unfortunately Shapways doesn’t offer manual removal of support material. If your part is not symmetrical, or has thin sections and thick sections there is a good chance it will warp in the support removal oven. You end up with bent parts or dimensional issues. I hope this explains things a bit. Ryan Mendell
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Re: Bridge girder on three PRR FM flat cars
Drew Bunn
Not to sound insulting, Claus - but I think you're seeing things. There is no way that load would remain upright unless it was perfectly centered on those flats. I've unloaded centerbeams, and two forklift operators have to remove the load evenly on both sides or the car will fall over. Cheers
On Sat., Dec. 21, 2019, 10:21 Claus Schlund \(HGM\), <claus@...> wrote:
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Re: Bridge girder on three PRR FM flat cars
Lloyd Keyser
Sorry, I just did not think of it. Lloyd Keyser
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Re: Bridge girder on three PRR FM flat cars
mel perry
out of curiousity, why weren't these comments/questions not included, in the OP?, where they belonged, instead of creating a seperate thtead? mel perry
On Sat, Dec 21, 2019, 9:13 AM Bill Lugg <luggw1@...> wrote: https://en.wikipedia.org/wiki/Classification_yard#Hump_yard
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Re: Bridge girder on three PRR FM flat cars
https://en.wikipedia.org/wiki/Classification_yard#Hump_yard
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"According to the PRRT&HS PRR Chronology, the first hump yard in the United States was opened May 11, 1903 as part of the Altoona Yards at Bells Mills (East Altoona). Other sources report the PRR yard at Youngwood, PA which opened in the 1880s to serve the Connellsville coke fields as the first U.S. hump yard." Only as far away as Google and Wikipedia. ;o) Bill Lugg
On 12/21/19 9:56 AM, Charles Peck wrote:
Lloyd's question raises another question. When was the first hump yard
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Re: Bridge girder on three PRR FM flat cars
Lloyd's question raises another question. When was the first hump yard built and where? Chuck Peck
On Sat, Dec 21, 2019 at 11:45 AM Lloyd Keyser <lloydkeyser@...> wrote:
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Re: Bridge girder on three PRR FM flat cars
Lloyd Keyser
Why is there not a Do No Hump sign on this load Lloyd Keyser
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Re: Bridge girder on three PRR FM flat cars
Claus Schlund \(HGM\)
Hi Brian and List Members,
Thanks Brian for calling our attention to
this.
I find it interesting that the bridge girder is NOT
mounted on the exact center of the trio of PRR class FM flat cars, and the
bridge girder is instead somewhat closer to the camera. This does two
things that I find somewhat puzzling...
(1) It imbalances the load on the trucks on the two
flats at the ends - for each of these two cars, one truck will be carrying more
load than the other truck
(2) It required the brake wheel on the flat
closest to the camera to be removed. Had the load been placed so it was in the
center, that car maybe could have kept its brake wheel in place, as is the case
on the flat furthest from the camera. Note there is a removed
brakewheel mounted to the deck of the flat closest to the camera, and
another removed brakewheel mounted on the deck of the flat furthest from the
camera - presumably this last one came off the midle flat car
Any thoughts on this?
Claus Schlund
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Bridge girder on three PRR FM flat cars
Brian Rochon
http://lists.railfan.net/erielackphoto.cgi?erielack-12-21-19/X5845.jpg
From EL photo archive today.
Brian Rochon
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Re: 3D printing (Was: New early P&R steel.....)
Tom Madden
Fine detail is a jet printing process. I believe the jet printers Shapeways is using are 600 x 600 DPI X & Y, and at 16 microns per layer the Z is 1600 DPI. (3D Systems has 750 x 750 DPI machines with 13 micron layer capability, and 1600 x 900 but only for 32 micron layers.)If these don't sound like very high resolution printers, remember that there are two jet nozzels per pixel - you can place either wax or body material at each location. Tom Madden
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