mudchickenSome structures were horribly overbuilt, but others you seem to have forgotten about didn't survive the first train. The narrow gage experience showed this plenty of times. The understanding of structures/statics and materials science + metalurgy had not yet been fully developed.
Some structures were horribly overbuilt, but others you seem to have forgotten about didn't survive the first train. The narrow gage experience showed this plenty of times. The understanding of structures/statics and materials science + metalurgy had not yet been fully developed.
Amen. We are fools if we look at history only for confirmation of our cherished beliefs of today.
RWM
Murph:
The track structure they laid is of course long, long gone, though I did some work in 2007 on a line still laid with its original 1903 60 lb. Minnequa rail. And some of the co-located splinter collections once called "ties" appeared to be original too.
Culverts and drainage structures such as you describe were not engineered with any knowledge or prediction of what loadings might be 100 years hence, nor were people at that time often even thinking there would be need for these structures that distant into the future. Their choices were limited to light-duty timber bridges using untreated low-quality timber that would be extremely expensive to maintain (with total replacement of every member on roughly a 3-5 year schedule), or stone-faced, rubble-filled structures that would be virtually maintenance-free -- and the cost differential between the two was not enormous. Once a decision was made for stone, the cost differential between engineering and constructing for the minimum-possible stone structure and something that was bulletproof was virtually nil.
Constructability, particularly with stone structures and hand labor, favors "heavy" anyway. There is no good way to build it light.
You don't need computers or even a pocket calculator to do 99% of the engineering we do today. You need common sense, experience, a pencil and paper, and good standards. The software is nice to have to do things like calculate earthwork quantities and size drainage openings. There is also software that purports to minimize earthwork and cut-and-fill quantities, and locate alignments, and you should see the wretched results they deliver! I once went to a demonstration by some very smart guys of how their software program could locate a rail line on virgin topography to minimize earthwork. The result didn't have hardly a stick of tangent rail in five miles, and bobbed up and down like a rowboat in a hurricane. In other words, it was utterly inoperable and unmaintainable. I wonder if they ever sold that to anyone other than some transit agency or DOT.
tree68 Starrucca Viaduct, well over 1000' long, is made of PA bluestone, IIRC, and was built about 1853. Of course, the Romans built some structures that still stand, but it still amazes me that they were able to construct such a structure with such tight tolerances, and as quickly as they did. And, with hand tools. It, too, is still in use, albeit with one track instead of two. One explanation for the longevity of the early engineer's work is that the technology has progressed, and the roadbeds they laid have benefitted from that advancement.
Starrucca Viaduct, well over 1000' long, is made of PA bluestone, IIRC, and was built about 1853. Of course, the Romans built some structures that still stand, but it still amazes me that they were able to construct such a structure with such tight tolerances, and as quickly as they did. And, with hand tools. It, too, is still in use, albeit with one track instead of two.
One explanation for the longevity of the early engineer's work is that the technology has progressed, and the roadbeds they laid have benefitted from that advancement.
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
Like most everybody else, I live in an area that had a lot of rail lines built 100+ years ago. I marvel at the thought that over a century before calculators and computers, railroad builers could build such long lasting track structures. This is especially true, when you consider that the train weights have increased over the last century. How did the engineers of old manage to be so ...good(?), without modern day equipment?
Locally, I know of quite a few stone arch bridges made out of pink Sioux Quartzite, for example. How did the designer know how to build such a structure, that would still be used, under much heavier loading conditions, 125 or so years later?
Thanks to Chris / CopCarSS for my avatar.
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