Date
1 - 10 of 10
Engineering characteristics of boxcar ends
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Robert G P
Hello everyone, Just wanted to ask if there is anywhere online/book where I could read about the engineering incorporated into boxcar ends (or even roofs)? I'm primarily interested in what made certain designs better than others and as the question addresses basically the engineering that goes into designing a boxcar end. What is the foundation of different designs? What makes one more efficient than the other? Pros/cons? Where were certain designs more prominent than others? There were so many different configurations (even some one offs) that makes this a fascinating topic. Ive come to learn the study of roofs/ends is a hobby all its own! Thanks, Robert |
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Dennis Storzek
In a word, patent avoidance. If any testing was ever done, and I doubt any direct testing between competing designs ever was, I'd say there was little significant difference between the Dreadnaught, P-S, and the end that Despatch shops used. The main reason for the differences was so P-S and Despatch could stamp their own ends and not have to pay royalties to the Standard Railway Equipment Co., owner of the Dreadnaught design. And, what was improved by the Improved Dreadnaught end was it offered SRECo. another seventeen years of patent protection.
That's not to say there was not improvement over time. The early Murphy corrugated end was stronger and lighter than all the flat plate ends that came before, but it was week at the corners. The original Dreadnaught design did nothing to address that, although the claim was made that the rib pattern made it easier to straighten a bowed end. The real improvement came with the round corner end combined with W section corner posts, which the others then copied. The movement from riveted attachment to welded fabrication led to more changes that we never discuss here, because they post date 1960. And so it goes, but the different designs popular in any given era were driven more by desire to not pay royalties rather than engineering. Dennis Storzek |
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Tony Thompson
Dennis Storzek wrote:I have read the same statement about the W-corner-post end, that it helped with corner stiffness, but the original reason was mostly to provide a better corner attachment for the inside wood sheathing. Apparently that was a bear with the original Dreadnaught ends. Tony Thompson tony@... |
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Ray Breyer
About the only place where you'll be able to read about the engineering behind freight car construction as it relates to ends, is in assorted early MCBA committee reports. Railroads knew that all-steel car construction was far better than wood (since the 1870s when the French built the first all-steel cars), but it took decades to gain acceptance in the industry. There's lots of MCBA discussion on steel body components through their annual reports. Kirkman advocates the use of steel ends, but doesn't really get into a detailed analysis as to why they're better. Ray Breyer Elgin, IL
On Friday, December 9, 2022 at 10:56:26 AM CST, Robert G P <bobgp5109@...> wrote:
Hello everyone,
Just wanted to ask if there is anywhere online/book where I could read about the engineering incorporated into boxcar ends (or even roofs)? I'm primarily interested in what made certain designs better than others and as the question addresses basically the engineering that goes into designing a boxcar end. What is the foundation of different designs? What makes one more efficient than the other? Pros/cons? Where were certain designs more prominent than others? There were so many different configurations (even some one offs) that makes this a fascinating topic. Ive come to learn the study of roofs/ends is a hobby all its own! Thanks, Robert |
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jace6315
At times, there's also the question of material availiability. Venturing briefly into the modern era, one of my former co-workers, Mike Hall, basically had to design a new fabricated end design when he worked at FMC during the IPD boxcar boom of the 1970's as there were no ends available from anyone at the time. Pullman surely wasn't selling any of their capacity to the competition. Jim
------- Original Message ------- On Friday, December 9th, 2022 at 12:48 PM, Dennis Storzek via groups.io <soolinehistory@...> wrote: In a word, patent avoidance. If any testing was ever done, and I doubt any direct testing between competing designs ever was, I'd say there was little significant difference between the Dreadnaught, P-S, and the end that Despatch shops used. The main reason for the differences was so P-S and Despatch could stamp their own ends and not have to pay royalties to the Standard Railway Equipment Co., owner of the Dreadnaught design. And, what was improved by the Improved Dreadnaught end was it offered SRECo. another seventeen years of patent protection. |
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Philip Dove
A factor in choice of material for making cars was also the length of cars and ease of maintenance. Europe useds wood for car sides and even ends sometimes even now but all these cars are far shorter. Many British railways built iron or steel sided "boxcars" of around 16 external length in the 1890s then reverted to wood because they were easier to repair. Pressed steel ends were used by one of the main rail companies from the 1930s. British railways used them almost exclusively for their massive standardised car building programmes of the 1950s. The ends appeared to be inspired by American ribbed ends. |
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jace6315
I
except that Dick Dawson will weigh in on this but in short, the AAR
manuals are a good place to start to read about the design requirements. You
want the ends to withstand the loads involved, often
from inside the car during impacts, with as little maintenance as
possible, keeping the load dry, at a low cost and low weight. Stamped,
corrugated ends generally do all of that well; corrugation allows for
the use of thinner material as compared to a flat end yet they typically
take up less volume than a sheet and post end (a la PRR X29). The stamped
sheet elimates bolted or riveted joints except around the perimeter of
the stamping (mainly); fewer holes usually means fewer problems with
leaks. Thinner material means less material and lower costs
while the stamping process minimizes labor costs, both in making the
sheets and in assembling them onto the car. Stamping and the design of the corrugations also allow for patented designs as noted by Dennis (if you're making the ends, you want them to be low cost, not low price!). The big drawback of stamped
ends is making enough of them to cover the high tooling costs involved. Standardized car heights and widths definitely helps in that you only need a few stamping sizes. The
loads on the ends are highest close to the floor, decreasing with height so two (or more) sheets were
common to allow for the use of thinner top sheet(s). This also gave some
flexibility with car heights with a few different sized stampings (again, keeping those stamping tooling costs low). Two
sheet arrangements became the standard to minimize seams. Single sheet
ends like the Van Dorn paid a penalty on weight (which translates
into cost) while the three panel Murphy's probably were more maintenance intensive. I wouldn't be surprised if the reverse end designs came into
vogue as a way to make it easier (cheaper) to design and install safety appliances on the ends of the cars (no offsets or brackets needed) but didn't perform as well plus they would eat up volume.
------- Original Message ------- On Friday, December 9th, 2022 at 11:55 AM, Robert G P <bobgp5109@...> wrote:
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David
One place to look is in the trade journals of the time (primarily Railway Mechanical Engineer, but sometimes Railway Age or Railway Review; these are generally available online for the era of this list). Every so often, there would be an article about some new roof or end design, which would typically point out the shortcomings of existing designs that the new product intended to address.
David Thompson |
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Dennis Storzek
On Fri, Dec 9, 2022 at 04:51 PM, jace6315 wrote:
I except that Dick Dawson will weigh in on this but in short, the AAR manuals are a good place to start to read about the design requirements.Unfortunately I don't think Dick is a member of this list. He is very knowledgeable but his interests lie during the period he worked in the industry. I wouldn't be surprised if the reverse end designs came into vogue as a way to make it easier (cheaper) to design and install safety appliances on the ends of the cars (no offsets or brackets needed) but didn't perform as well plus they would eat up volume.Actually the "reverse" versions of most ends were the first to be offered... Both the Murphy corrugated end and the Dreadnaught were first offered with the ribs facing inward, I suppose because it looked like that would be better able to resist shifting loads. Problem is, that left the end lining poorly supported. The manufacturers eventually realized that with the ribs faced outward the nailing strips could placed in the ribs and the bulk of the lining was against the flat sheet of the end. Dennis Storzek |
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Dennis Storzek
On Fri, Dec 9, 2022 at 05:17 PM, David wrote:
One place to look is in the trade journals of the time (primarily Railway Mechanical Engineer, but sometimes Railway Age or Railway Review; these are generally available online for the era of this list).The problem is, those articles are mostly hype, because they were written by the manufacturer of the product. There were very few independent tests conducted that compared how these products actually performed. Dennis Storzek |
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