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Definition of a Fishbelly Underframe


Bill Welch
 

Was there a formula or dimensions or some other basis that was used
to define what constituted a "fishbelly" underframe. I ask because
while the u/f of the USRA's 40-ton DS car was obviously this type of
underframe and is usually identified as such, other car designs, the
PRR's X23/R7 for example, had a centersill that was deeper at their
center portions but narrowed towards the bolsters. Sort a "trimmer"
fishbelly if you will. I have never noticed these cars as being
referred to as having a fishbelly u/f. An even trimmer example would
be the Bettendorf u/f profile.

I am mainly trying to understand how to more precisely apply the
term, or better, when not to apply the term "fishbelly?"
Bill Welch
2225 Nursery Road; #20-104
Clearwater, FL 33764-7622
727.470.9930
fgexbill@tampabay.rr.com


Richard Hendrickson
 

On May 16, 2011, at 2:31 PM, Bill Welch wrote:

Was there a formula or dimensions or some other basis that was used
to define what constituted a "fishbelly" underframe. I ask because
while the u/f of the USRA's 40-ton DS car was obviously this type of
underframe and is usually identified as such, other car designs, the
PRR's X23/R7 for example, had a centersill that was deeper at their
center portions but narrowed towards the bolsters. Sort a "trimmer"
fishbelly if you will. I have never noticed these cars as being
referred to as having a fishbelly u/f. An even trimmer example would
be the Bettendorf u/f profile.

I am mainly trying to understand how to more precisely apply the
term, or better, when not to apply the term "fishbelly?"
Bill, I thought the Car Builders' Dictionaries/Cyclopedias might
provide some guidance and, in a way, they do. The 1922 issue does
not define "fish-belly," but uses the term several times in its
definition of "center sill." implying a deep built-up riveted
structure (e.g., the USRA 40 ton center sill). The 1931 issue has an
entry for "fish-belly sill" but, curiously, describes it only as to
applies to passenger cars. Again, it is defined as a deep
structure. So where does that leave the Bettendorf underframe, the
railroad-designed underframe on 1920s and '30s PFE cars, or the
Pennsy X23/R7 underframe? The CBCycs don't help, but my inclination
is to describe those as shallow fishbelly underframes, since they
definitely have a section between the bolsters that extends down
below the bolsters, but doesn't extend down very far.

Richard Hendrickson


Dennis Storzek
 

--- In STMFC@yahoogroups.com, Bill Welch <fgexbill@...> wrote:

Was there a formula or dimensions or some other basis that was used
to define what constituted a "fishbelly" underframe. I ask because
while the u/f of the USRA's 40-ton DS car was obviously this type of
underframe and is usually identified as such, other car designs, the
PRR's X23/R7 for example, had a centersill that was deeper at their
center portions but narrowed towards the bolsters. Sort a "trimmer"
fishbelly if you will. I have never noticed these cars as being
referred to as having a fishbelly u/f. An even trimmer example would
be the Bettendorf u/f profile.

I am mainly trying to understand how to more precisely apply the
term, or better, when not to apply the term "fishbelly?"
Bill Welch
Bill,

The Car Builder's Cyclopedia started life as the Car Builder's Dictionary, with the express purpose of standardizing the terminology. As such, I tend to use, and stand by, the definitions it gives. Here is what the 1980 edition says, picked up, I'm sure, from earlier editions:

"Fish-Belly Sill. A term used to describe a type of center sill construction consisting of shallow sections at each end with transitions to a deeper section at the center. Fish-belly sills are often used on long cars which need heavier sections at the center."

Note it doesn't say how much deeper the section is, and I would assume the intent that anything other than structural shapes that pass through the bolster could be considered a "fish-belly sill" if the section increases somewhere between the bolsters.

Dennis


Richard Hendrickson
 

On May 16, 2011, at 5:34 PM, soolinehistory wrote:

he Car Builder's Cyclopedia started life as the Car Builder's
Dictionary, with the express purpose of standardizing the
terminology. As such, I tend to use, and stand by, the definitions
it gives. Here is what the 1980 edition says, picked up, I'm sure,
from earlier editions:

"Fish-Belly Sill. A term used to describe a type of center sill
construction consisting of shallow sections at each end with
transitions to a deeper section at the center. Fish-belly sills are
often used on long cars which need heavier sections at the center."

Note it doesn't say how much deeper the section is, and I would
assume the intent that anything other than structural shapes that
pass through the bolster could be considered a "fish-belly sill" if
the section increases somewhere between the bolsters.
Thanks, Dennis. After my earlier post on this subject, I went
looking further and found in the 1953 CBCyc this shorter definition:
"Fish-belly sill. A type of heavy, deep, built up side or center
sill. Profile resembles that of a fish, hence the name." The use of
the word "heavy" here would seem to exclude a shallow fishbelly sill,
whereas the 1980 definition would include sills with a shallower
section between the bolsters."


Richard Hendrickson


al_brown03
 

Hmm ... it sounds as though one might define a "deep" fishbelly as being consistent with both definitions, and a "shallow" fishbelly as consistent with only the less restrictive one. Can that be expressed quantitatively?

Al Brown, Melbourne, Fla.

--- In STMFC@yahoogroups.com, Richard Hendrickson <rhendrickson@...> wrote:

On May 16, 2011, at 5:34 PM, soolinehistory wrote:

he Car Builder's Cyclopedia started life as the Car Builder's
Dictionary, with the express purpose of standardizing the
terminology. As such, I tend to use, and stand by, the definitions
it gives. Here is what the 1980 edition says, picked up, I'm sure,
from earlier editions:

"Fish-Belly Sill. A term used to describe a type of center sill
construction consisting of shallow sections at each end with
transitions to a deeper section at the center. Fish-belly sills are
often used on long cars which need heavier sections at the center."

Note it doesn't say how much deeper the section is, and I would
assume the intent that anything other than structural shapes that
pass through the bolster could be considered a "fish-belly sill" if
the section increases somewhere between the bolsters.
Thanks, Dennis. After my earlier post on this subject, I went
looking further and found in the 1953 CBCyc this shorter definition:
"Fish-belly sill. A type of heavy, deep, built up side or center
sill. Profile resembles that of a fish, hence the name." The use of
the word "heavy" here would seem to exclude a shallow fishbelly sill,
whereas the 1980 definition would include sills with a shallower
section between the bolsters."


Richard Hendrickson



[Non-text portions of this message have been removed]


Dennis Storzek
 

--- In STMFC@yahoogroups.com, "al_brown03" <abrown@...> wrote:

Hmm ... it sounds as though one might define a "deep" fishbelly as being consistent with both definitions, and a "shallow" fishbelly as consistent with only the less restrictive one. Can that be expressed quantitatively?

Al Brown, Melbourne, Fla.
Please keep in mind that it is not the purpose of a dictionary to coin new terms, but rather explain terms that have come into common usage. As such, they lag behind the language.

It would appear that the term was first applied to passenger cars with deep sills AFTER cars with straight sills began to be built, since before that there was no reason to differentiate, as all passenger cars had deep sills. The term then evolved to mean ANY application with sills of unequal cross section over the length of the car.

Dennis


ROGER HINMAN
 

http://books.google.com/books?id=RE1QAAAAYAAJ&pg=PA229&lpg=PA229&dq=fishbelly+center+sill&source=bl&ots=-2_LmL1b57&sig=NOuEWEDzsNWRenJ-zAudOcslinc&hl=en&ei=TW3STZtpwdyBB6653NML&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBYQ6AEwAA#v=onepage&q=fishbelly%20center%20sill&f=false
On May 16, 2011, at 5:31 PM, Bill Welch wrote:

Was there a formula or dimensions or some other basis that was used
to define what constituted a "fishbelly" underframe. I ask because
while the u/f of the USRA's 40-ton DS car was obviously this type of
underframe and is usually identified as such, other car designs, the
PRR's X23/R7 for example, had a centersill that was deeper at their
center portions but narrowed towards the bolsters. Sort a "trimmer"
fishbelly if you will. I have never noticed these cars as being
referred to as having a fishbelly u/f. An even trimmer example would
be the Bettendorf u/f profile.

I am mainly trying to understand how to more precisely apply the
term, or better, when not to apply the term "fishbelly?"
Bill Welch
2225 Nursery Road; #20-104
Clearwater, FL 33764-7622
727.470.9930
fgexbill@tampabay.rr.com





[Non-text portions of this message have been removed]