I enjoyed building the bridge for the Summer Structure Challenge, so will do another! This is another prototype bridge that is about 2 miles south of the Challenge bridge. On the layout, it will be about 8 feet from the other bridge - selective compression. It is an interesting bridge in that it appears to be a rebuilt timber structure - seems they cut the wooden bent pole down a bit, then added some concrete beams and some steel I-beams up above. As measured by GoogleEarth, the bridge is 170 feet long and 16.5 feet wide - funny that on Bing, the bridge appears much wider but alot shorter than the real thing. Should be a fun project. I won't build it as a strictly prototype match, will make some adjustments to fit the layout, but it should be close.

This will be built from styrene, got most of the structural stuff yesterday and got some nut-bolt-washer castings today.

Some images:

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And a bing map:

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What an interesting bridge! I hope that wasn't poison ivy growing along the side!

In that one shot from underneath, it looks like they might have used your rectangular conduit idea Gary...!

Andrew

Andrew, it does look like that Din Rail. But on closer examination, it is 4 seperate 12" x 12" I-beams running the length of the bridge. I don't know for a fact, but it sure seems that this was once an entirely wooden trestle that was refurbished at some point, with the concrete bent toppers and the I-beams.

Well, here is a photo of the model bridge, all the various sizes of styrene to represent the lumber and concrete, plus some Evergreen I-beams. Also, a pile of nut-bolt-washer castings.

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You are right, Gary. I see no reason for a bridge to be built like that. They must have rebuilt the bridge for some reason, and decided the wooden pilings good enough to reuse with a rebuilt deck. I wonder if the original deck had caught fire.

Fire is a possibility, but I am thinking that the original bridge was built sometime ago, and as locomotives and loaded car weights went up, they refurbished the bridge to handle the heavier traffic. I am imagining that the engineering department determined that the six large-diameter poles per bent, with the bents 14 feet apart, was plenty enough for the increased capacity needs, but the rest of the bridge was no longer strong enough. So, they removed the deck, cut off the poles, and added the pre-cast concrete toppers on them. Then the 4 I-beams on top of that, then a new deck.

Nice project ! This too, will be interesting to follow, go for it, and have fun!
I will be looking to see just how you model the vines, growing on those bents.

S250, on the vines - the other day I was using one of those green "scouring pad" "scotch-brite" kind of things, and started pulling it apart - it came off kind of stringy viney, so there aresome possibilities there.

I plan to get started on the bridge this weekend - very much looking forward to it.

Here ia a section drawing of the bridge - not sure exactly how the deck is done on the inside. Would they have simply filled the trough with ballast and put the ties over like shown? Or would the ties be on some wooden supporting structure? Not that it matters, as it is all covered by ballast, but just wondering. I'm thinking that the ties would be supported solely by the ballast.

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And another Bing view:

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I think the ties would "float", otherwise what is the purpose of ballasting the bridge at all?

nachoman Wrote:I think the ties would "float", otherwise what is the purpose of ballasting the bridge at all?

Well, that does make sense! I knew there was a reason why I figured the ties just sat on the ballast.

Gary...Much as I admire your modeling, that workbench of yours sent a shiver up my spine....Shame on you....!!!
How can you work in such orderliness..??

Looking forward to this build....

Styrene, to represent wood? And you thought rusting concrete was a challenge!

What I mean to say is, I'm looking forward to see how you treat the styrene to make it look like wood.

Why not use wood dowels? An issue with glue strength?

Galen

Gus: The workbench seems to be in a constant state of flux. As I work on projects, the clutter steadily grows to the point that I cannot take it any more, then I spend 3 hours cleaning up. For awhile, it is a wonderful place to work, but here we go again, the clutter begins to build..... and around n' around we go! Now, the disgraceful thing is that my workbench has the potential to be a very organized place - because I have a place where everything goes. But I am too lazy to put stuff back as it is used, and before long, I can't find anything and my 10 square foot workarea has shrunk to about 1 usable square foot.

Galen: My first thought was to use real wood, but styrene has always seemed easy to work with, and I knew there were techniques for making it look like wood, and thus my choice. I spent a bit of time experimenting the other day to see what I could do on the faux-wood. Here are some samples, they turned out somewhat satisfactorily.

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Nice work.

Gary,

These are some great looking piers!!
I really like texture you have added to them and the coloration is very well done. I was impressed at how quickly you completed the other bridge and I look forward to the same rate of progress :mrgreen:

Keep up the great work and we are all waiting to see what technique you decide to use!!