Hi:

In the last few days I've gotten some back issues of the RPC and taken a good look at some of the files here and on the Steam Freight Cars site, all of which has left me a little confused about how various AAR boxcars are defined.

As best as I can tell, there were four main types: 1937, 1937 (modified), 1944, and postwar. What distinguishes theses from each other? I'm pretty sure that 40-6 x 9-2 x 10-0 cars are the 1937 types and that 40-6 x 9-4 x 10-6 cars are postwar, but what are the others and how much leeway in dimensions is there within a type? For example, looking at RPC 4 pages 12 to 34 I see:

NC &STL 18850 9-2 x 10-0 "1937 AAR"
CB&Q 35000 9-4 x 10-6 "AAR" (blt 5-47)
ATSF 143510 9-2 x 10-4 "1937 (modified) AAR"
CNW 71028 9-2 x 10-5 "1937 (modified) AAR"
CNW 80606 9-2 x 10-6 "1937 (modified) AAR"
UP 197899 9-2 x 10-6 "1944 AAR"
SOUTHERN 23399 9-2 x 10-6 "AAR" (blt 8-47)
MP 37447 9-2 x 10-6 "AAR" (blt 8-57)

Thanks in advance,
KL

On Dec 15, 2006, at 10:48 AM, Kurt Laughlin wrote:

In the last few days I've gotten some back issues of the RPC and taken a good look at some of the files here and on the Steam Freight Cars site, all of which has left me a little confused about how various AAR boxcars are defined.

As best as I can tell, there were four main types: 1937, 1937 (modified), 1944, and postwar. What distinguishes theses from each other? I'm pretty sure that 40-6 x 9-2 x 10-0 cars are the 1937 types and that 40-6 x 9-4 x 10-6 cars are postwar, but what are the others and how much leeway in dimensions is there within a type?

Kurt, your analysis is essentially correct, though there were actually five main variations: 1932, 1937, 1937 modified, 1944, and postwar. the 1932 cars were 9'4" high inside, the 1937 versions were 10'0" high inside, and subsequent versions were all 10'6" or thereabouts. Minor variations in inside dimensions are seldom significant, as they generally reflected nothing more than the application of different roofs (e.g., Viking corrugated instead of Murphy rectangular panel)) or differences in the thickness of wood floor and interior linings. Hence some 1937 modified cars were 10'4" or 10'5" IH, but in any case the salient spotting feature was 5-5 Dreadnaught ends. The shift from 1937 modified to 1944 wasn't recognized by the AAR, since construction and dimensions didn't change, but modelers use the 1944 designation to identify cars with postwar 4-4 Improved Dreadnaught ends. "Postwar" is tricky; I assume it represents the shift to the later style Dreadnaught ends with straight-tapered main ribs and rectangular top rib, but of course many cars of the 1944 design were built after WW II and what you're identifying as "postwar" AAR cars didn't appear until the 1950s.

Richard Hendrickson

Kurt Laughlin wrote:

As best as I can tell, there were four main types: 1937, 1937 (modified), 1944, and postwar. What distinguishes theses from each other?

This isn't a simple question, Kurt, and I don't think you can answer it with dimensions alone. Various buyers chose their own interior height, in particular, and so cars otherwise meeting, for example the original 1937 design, could vary a fair amount in dimensions. The 1944 design really isn't different from the prewar cars except that the "Improved Dreadnaught" end was shown. In October, 1947, the AAR drawings changed to 10 ft. 6 in. inside height, but not all roads were buying cars with that size.
I think you can do better by looking at features visible in photographs. But someone who has spent a lot of time with these cars, such as Ed Hawkins or Richard Hendrickson, may feel that there are also characteristic or "signature" dimensions. If so, I'd like to hear about it.

Tony Thompson Editor, Signature Press, Berkeley, CA
2906 Forest Ave., Berkeley, CA 94705 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@...
Publishers of books on railroad history

Richard Hendrickson wrote:

"Postwar" is tricky; I assume it represents the shift to the
later style Dreadnaught ends with straight-tapered main ribs and
rectangular top rib, but of course many cars of the 1944 design were
built after WW II and what you're identifying as "postwar" AAR cars
didn't appear until the 1950s.

I'll admit to not thinking too much about many post WWII cars as my
interests fade before 1951... but in my ignorance of 1950-1960 car
appearances I always thought of the diagonal panel roof as a major
characteristic of what you'd notice that would be a strong indicator that
set post war cars apart from pre-8/1945 boxcar construction.

Dave Nelson

--- In STMFC@..., "Dave Nelson" <muskoka@...> wrote:

I'll admit to not thinking too much about many post WWII cars as my
interests fade before 1951... but in my ignorance of 1950-1960 car
appearances I always thought of the diagonal panel roof as a major
characteristic of what you'd notice that would be a strong indicator

that

set post war cars apart from pre-8/1945 boxcar construction.

Dave Nelson

I tend to agree. The ends changed to the new pattern "Improved
Dreadnaught end" in 1944, but the roof remained the rectangular panel
design that had been in use since the thirties. About 1948, the ends
changed again to the improved IDE designn with the rectangular rib on
top, and almost concurrently the roofs changed to diagonal panels, and
the doors changed to the "Improved Youngstown" design. A car with all
three of these improvements is what I'd call a post-war AAR car.

Incidentally, while much has been made of the fact that the shape of
the major ribs on the IDE changed from the "rolling pin" shape to a
straighter taper, few people note that there are at least two
variations of panels on the diagonal panel roofs, not including the
different panels made to work with the AAR "ZU" eave, which most
modelers call an overhanging roof.


Dennis

Thanks Richard

From: Richard Hendrickson

Kurt, your analysis is essentially correct, though there were actually
five main variations: 1932, 1937, 1937 modified, 1944, and postwar.

Well, that's my fault. I didn't include the 1932 series because I thought they were ARA not AAR.

the 1932 cars were 9'4" high inside, the 1937 versions were 10'0" high
inside, and subsequent versions were all 10'6" or thereabouts. Minor
variations in inside dimensions are seldom significant, as they
generally reflected nothing more than the application of different
roofs (e.g., Viking corrugated instead of Murphy rectangular panel)) or
differences in the thickness of wood floor and interior linings. Hence
some 1937 modified cars were 10'4" or 10'5" IH, but in any case the
salient spotting feature was 5-5 Dreadnaught ends.

OK, another factor.

The shift from 1937
modified to 1944 wasn't recognized by the AAR, since construction and
dimensions didn't change, but modelers use the 1944 designation to
identify cars with postwar 4-4 Improved Dreadnaught ends. "Postwar" is
tricky; I assume it represents the shift to the later style Dreadnaught
ends with straight-tapered main ribs and rectangular top rib, but of
course many cars of the 1944 design were built after WW II and what
you're identifying as "postwar" AAR cars didn't appear until the 1950s.

So then, if I'm sorting this out correctly for 40-6 IL cars, the nominal configuration was:

1932 AAR: 8-9 IW x 9-4 IH; 5/5 Dreadnaught ends (DE)
1937 AAR: 9-2 x 10-0; 5/5 DE
1937 Modified AAR: 9-2 x 10-4 to 10-6; 5/5 DE
1944 AAR: 9-2 x 10-6; 4/4 Improved DE
"Postwar" AAR: 9-4 x 10-6; 1/3/4 Improved DE

This leads me to another question: Were the actual 5/5 DE panels the same for a 10-0 IH car as a 10-3, 10-4, 10-5, or 10-6 car?

I see part of my initial confusion is that Ed Hawkins has a list on Steam Era Freight Cars that is labeled "Postwar" on the site's intro page but "1944" on the actual file.

While we may have our RPC #4s out, am I correct in captioning the ends shown on page 7 as 4/5 DE (VGN); 4/4 IDE (NYC); 3/4 IDE (WM); and 1/3/4 IDE (LV)?

Thanks again,
KL

On Dec 15, 2006, at 1:10 PM, Dave Nelson wrote:

Richard Hendrickson wrote:

"Postwar" is tricky; I assume it represents the shift to the
later style Dreadnaught ends with straight-tapered main ribs and
rectangular top rib, but of course many cars of the 1944 design were
built after WW II and what you're identifying as "postwar" AAR cars
didn't appear until the 1950s.

I'll admit to not thinking too much about many post WWII cars as my
interests fade before 1951... but in my ignorance of 1950-1960 car
appearances I always thought of the diagonal panel roof as a major
characteristic of what you'd notice that would be a strong indicator that
set post war cars apart from pre-8/1945 boxcar construction.

Dave, the problem here is that diagonal panel roofs were introduced ca. 1948 and many of what we're in the habit of calling 1944 AAR box cars, i.e. those with 4-4 "rolling pin taper" Improved Dreadnaught ends, were built with diagonal panel roofs.

Richard Hendrickson

On Dec 15, 2006, at 1:52 PM, Kurt Laughlin wrote:

1932 AAR: 8-9 IW x 9-4 IH; 5/5 Dreadnaught ends (DE)

No. 4/4 Dreadnaught on most cars, though some exceptions included 4-5 and 7-8 corrugated.

1937 AAR: 9-2 x 10-0; 5/5 DE

No; 4/5 Dreadnaught.

1937 Modified AAR: 9-2 x 10-4 to 10-6; 5/5 DE
1944 AAR: 9-2 x 10-6; 4/4 Improved DE
"Postwar" AAR: 9-4 x 10-6; 1/3/4 Improved DE

This leads me to another question: Were the actual 5/5 DE panels the same
for a 10-0 IH car as a 10-3, 10-4, 10-5, or 10-6 car?

10-0 IH cars had 4/5 ends; almost all 10-4 and higher cars had 5/5 ends. Lower panels were essentially the same in all cases, but some 10'4 cars
had slightly shorter top ribs so they would fit inside the eave insets at the top corners. Worth noting, also, that Dreadnaught ends made prior to 1939/-40 had square corners; later, both 4/5 and 5/5 ends had W corner posts and round corners.

While we may have our RPC #4s out, am I correct in captioning the ends shown
on page 7 as 4/5 DE (VGN); 4/4 IDE (NYC); 3/4 IDE (WM); and 1/3/4 IDE (LV)?

Yes. Note, though, that the LV car still had the "rolling pin" style main ribs; for illustrations of the later style main ribs, see the photos of the Lackawanna cars on p.27.

Richard Hendrickson

OK then, just to it all in one place. . .

Nominal or "most common" configurations:

1932 ARA: 8-9 IW x 9-4 IH; 4/4 Dreadnaught ends (DE); square corners only; various roofs
1937 AAR: 9-2 x 10-0; 4/5 DE; square or round corners; various roofs
1937 Modified AAR: 9-2 x 10-4 to 10-6; 5/5 DE; round corners only; various roofs
1944 AAR: 9-2 x 10-6; 4/4 Improved DE; round corners only; various roofs
"Postwar" AAR: 9-4 x 10-6; 1/3/4 Improved DE; round corners only; diagonal panel roof

Sound right?

Thanks everyone,
KL

--- In STMFC@..., "Kurt Laughlin" <fleeta@...> wrote:

----- Original Message -----
From: Dennis Storzek

. . . variations of panels on the diagonal panel roofs, not

including the

different panels made to work with the AAR "ZU" eave, which most
modelers call an overhanging roof.
----- Original Message -----

Was ZU a brand name or a descriptive name indicating a cross-section

at the

eave made from a car builder's zee section attached to a car builder's
channel section?

KL

It was the AAR's descriptive terminology. The original "Z bar eave"
was indeed a length of standard rolled structural mill shape. The ARA
early on realized what an elegant solution it was to fastening the
then becoming popular all steel roofs to the fabricated sides of a
steel boxcar, bought the rights, and made it available royalty free to
the industry. Eventually, a pressed shape was substituted for the
rolled mill shape, and this presented the solution to attaching the
roof panels on an insulated car where there was no easy access to buck
the rivets once the insulation and lining were installed; they simply
formed a Z with one longer flange, then flanged that over again. The
result was a Z section with one flange formed into a U. The roof
sheets could then be riveted to the flange of the U, and both ends of
the rivet were accessible from the outside of the car.

There are some few examples of these "overhanging roofs" used on
reefers built in the thirties that pre-date the special ZU section,
the overhanging flange was formed by riveting a rolled angle section
to the upstanding flange of the Z. These can be identified in photos
from the line of rivets in the slot under the edge of the roof. I
believe these are properly called overhanging roofs, as I don't
believe the ZU name was coined until the one piece formed section was
developed.

Dennis

Kurt Laughlin wrote:

"Postwar" AAR: 9-4 x 10-6; 1/3/4 Improved DE

Probably we need to also divide the "rolling-pin" taper ends from the "banana-taper" ends, the latter introduced in Fall, 1954.

Tony Thompson Editor, Signature Press, Berkeley, CA
2906 Forest Ave., Berkeley, CA 94705 www.signaturepress.com
(510) 540-6538; fax, (510) 540-1937; e-mail, thompson@...
Publishers of books on railroad history

Richard Hendrickson wrote:

Dave, the problem here is that diagonal panel roofs were introduced
ca. 1948 and many of what we're in the habit of calling 1944 AAR box
cars, i.e. those with 4-4 "rolling pin taper" Improved Dreadnaught
ends, were built with diagonal panel roofs.

Them's post war cars, right? 8-)

I guess it comes down to are we trying to describe the 1944 standard
specifically or post war in general. If the former, then the roof "style"
isn't a spotting feature whereas if we're talking about the later term it
works fairly well -- not perfect, but well.

Going back to the '44 standard boxcar, I'd be looking for 40' length, ends
"more modern" than 5/5 dreadnaught, AND not a PS-1. Again, not perfect but
it serves me fairly well.

Dave Nelson

On Dec 15, 2006, at 12:48 PM, Kurt Laughlin wrote:

As best as I can tell, there were four main types: 1937, 1937
(modified), 1944, and postwar. What distinguishes theses from each
other? I'm pretty sure that 40-6 x 9-2 x 10-0 cars are the 1937 types
and that 40-6 x 9-4 x 10-6 cars are postwar, but what are the others
and how much leeway in dimensions is there within a type? For example,
looking at RPC 4 pages 12 to 34 I see:

NC &STL 18850 9-2 x 10-0 "1937 AAR"
CB&Q 35000 9-4 x 10-6 "AAR" (blt 5-47)
ATSF 143510 9-2 x 10-4 "1937 (modified) AAR"
CNW 71028 9-2 x 10-5 "1937 (modified) AAR"
CNW 80606 9-2 x 10-6 "1937 (modified) AAR"
UP 197899 9-2 x 10-6 "1944 AAR"
SOUTHERN 23399 9-2 x 10-6 "AAR" (blt 8-47)
MP 37447 9-2 x 10-6 "AAR" (blt 8-57)

Thanks in advance,
KL

Kurt,
Since you specifically called out some RP CYC references, I'll comment
and provide some specific references. To begin, Richard and Tony are
right when they say it's not an easy question to answer!

For background, the Car Builders' Cyclopedias, which use A.A.R.
terminology, specify the "1937 A.A.R. design" (i.e., page 110 of the
1940 CBC). Generally, this design was for a standard 40'-6" box car
with 10'-0" IH (some variations existed). The majority of these cars
had Dreadnaught Steel Ends (4/5 corrugation pattern) and Murphy raised
panel roofs, however, there were box cars built that met the design
criteria having other ends and/or roofs (such as Buckeye ends,
Pullman-Standard Corrugated Ends, 5/5 Dreadnaught Steel Ends used by
CP, "NSC" ends used on numerous CN cars, Viking roofs). Prior to this
was the 1932 A.A.R. box car (originated by the A.R.A.), and a drawing
of this car is shown on page 113 of the 1940 CBC. The standard IH was
9'-4". Again, there were variations of the inside height, and there
were all kinds of variations of roofs and ends, causing this "standard"
car to be anything but standard from the standpoint of a plastic
manufacturer thus far unable to justify tooling cost. To this day we
have no good plastic models of the 1932 "standard design" box car that
Ted Culotta wrote an entire book about.

In the 1946 CBC is a drawing and photo of an Erie 40'-6" box car
(81000-81799), and it states "Modified A.A.R. Standard" on page 110 as
part of the drawing title. It also specifies "Modified 1937 A.A.R.
design" on page 111 as part of the photo caption. These cars had an
inside height of 10'-4 3/8", and they were essentially the same as the
1937 A.A.R. design except taller and used 5/5 Dreadnaught Steel Ends.
In my roster list of "Modified 1937 A.A.R. standard box cars," I
extended the definition to include A.A.R. design box cars with 5/5
Dreadnaught Steel Ends regardless of the inside height, basically to
cover cars from 10'-4" to 10'-6" IH. In 1941 the A.A.R. approved an
optional increase in the inside height from 10'-0" to 10'-6". Therefore
the earliest 10'-6" A.A.R. box cars are sometimes referred to as the
"1941 A.A.R. design," however I've not found any official use of this
term in a drawing notation. At any rate, references to the "Modified
1937 A.A.R." and "1941 A.A.R. design" should be considered synonymous
in their intent.

Now to the "postwar" terminology. First, the A.A.R. never used the term
"postwar" in their terminology that I know of. Moreover, I have never
found an official reference to anything called a "1944 A.A.R. standard
design." If anyone knows of an official source where the 1944 A.A.R.
terminology exists, please advise accordingly. The "1944 AAR"
terminology was used by C&BT Shops to identify their models, but the
term is strictly a modeler's term as far as I can tell. I believe the
reference Pat Wider used in RP CYC Volume 4 (UP box car caption) is
actually incorrect. This is something the proofreader (me) should have
caught and modified. The terminology should have been either the
generic use of "postwar" (lower case "p") or to leave off the year
reference.

All subsequent references in CBCs (1949/51 through 1960) are specified
as "A.A.R. Standard box cars" and they make no distinctions of the
variety of door opening sizes, roofs, and ends that were used. Per page
72 of the 1953 CBC, the Car Construction Committee revised the standard
box car designs in 1951 to show both a 6' and 8' door opening and to
incorporate other minor structural changes (drawing shown on page 76).
The 1953 CBC also stated that in Oct. 1947 the Car Construction
Committee revised the drawings of the 40'-6" box car to change the
inside height from 10'-0" to 10'-6" because "there had been little
demand for the 10'-0" height." Perhaps SP and B&O would argue that
point.

Also during the postwar period was the widespread use of welded
underframes that had only limited usage on the cars of the 1937
designs. It's analogous to the AC&F Type 27 tank car. Once welded
underframes began being used by AC&F, the "Type 27" designation
disappeared with no new designation made, just the generic term "tank
car."

As we know, "postwar" cars of 10'-4" to 10'-6" IH used a variety of
ends and roofs over 15+ years of production. In my rosters and
writings, I have used the term "postwar A.A.R. box car" not as an
official A.A.R. term, but to refer to a family of box cars generally
built from mid-1945 (first use of the Improved Dreadnaught End that I
could find) to 1960, where we cut off the discussion per STMFC
requirements.
Regards,
Ed Hawkins

Thanks Ed, Tony, Dennis, and Richard. I'll have to digest all this and see how it fits in with my layout planning.

I'm glad I'm doing this a a hobby rather than a job. . .

KL

I will interject my two cents that an AAR (and 1932 ARA) box car has almost nothing to do with dimensions and everything to do with design traits. I likely could not cite all of things here, but many of them have to do with such things as the zee bar center sill sections welded along an adjacent edge, the side sills comprised of two components (an angled section on top with a lower section below it comprised of either non-continuous "tabbed" sections or a full length channel), the height of the center sill, along with many other subtle things. I will take this opportunity to say that these characteristics are covered in the 1932 ARA box car book in both the early chapters as well as the appendices.

Regards,
Ted Culotta

Speedwitch Media
645 Tanner Marsh Road, Guilford, CT 06437
info@...
www.speedwitch.com
(650) 787-1912

--- In STMFC@..., Ed Hawkins <hawk0621@...> wrote:

On Dec 15, 2006, at 12:48 PM, Kurt Laughlin wrote:

As best as I can tell, there were four main types: 1937, 1937
(modified), 1944, and postwar. What distinguishes theses from each
other? I'm pretty sure that 40-6 x 9-2 x 10-0 cars are the 1937 types
and that 40-6 x 9-4 x 10-6 cars are postwar, but what are the others
and how much leeway in dimensions is there within a type? For

example,

looking at RPC 4 pages 12 to 34 I see:

NC &STL 18850 9-2 x 10-0 "1937 AAR"
CB&Q 35000 9-4 x 10-6 "AAR" (blt 5-47)
ATSF 143510 9-2 x 10-4 "1937 (modified) AAR"
CNW 71028 9-2 x 10-5 "1937 (modified) AAR"
CNW 80606 9-2 x 10-6 "1937 (modified) AAR"
UP 197899 9-2 x 10-6 "1944 AAR"
SOUTHERN 23399 9-2 x 10-6 "AAR" (blt 8-47)
MP 37447 9-2 x 10-6 "AAR" (blt 8-57)

Thanks in advance,
KL

Kurt,
Since you specifically called out some RP CYC references, I'll comment
and provide some specific references. To begin, Richard and Tony are
right when they say it's not an easy question to answer!

For background, the Car Builders' Cyclopedias, which use A.A.R.
terminology, specify the "1937 A.A.R. design" (i.e., page 110 of the
1940 CBC). Generally, this design was for a standard 40'-6" box car
with 10'-0" IH (some variations existed). The majority of these cars
had Dreadnaught Steel Ends (4/5 corrugation pattern) and Murphy raised
panel roofs, however, there were box cars built that met the design
criteria having other ends and/or roofs (such as Buckeye ends,
Pullman-Standard Corrugated Ends, 5/5 Dreadnaught Steel Ends used by
CP, "NSC" ends used on numerous CN cars, Viking roofs). Prior to this
was the 1932 A.A.R. box car (originated by the A.R.A.), and a drawing
of this car is shown on page 113 of the 1940 CBC. The standard IH was
9'-4". Again, there were variations of the inside height, and there
were all kinds of variations of roofs and ends, causing this "standard"
car to be anything but standard from the standpoint of a plastic
manufacturer thus far unable to justify tooling cost. To this day we
have no good plastic models of the 1932 "standard design" box car that
Ted Culotta wrote an entire book about.

In the 1946 CBC is a drawing and photo of an Erie 40'-6" box car
(81000-81799), and it states "Modified A.A.R. Standard" on page 110 as
part of the drawing title. It also specifies "Modified 1937 A.A.R.
design" on page 111 as part of the photo caption. These cars had an
inside height of 10'-4 3/8", and they were essentially the same as the
1937 A.A.R. design except taller and used 5/5 Dreadnaught Steel

Ends....

As we know, "postwar" cars of 10'-4" to 10'-6" IH used a variety of
ends and roofs over 15+ years of production. In my rosters and
writings, I have used the term "postwar A.A.R. box car" not as an
official A.A.R. term, but to refer to a family of box cars generally
built from mid-1945 (first use of the Improved Dreadnaught End that I
could find) to 1960, where we cut off the discussion per STMFC
requirements.
Regards,
Ed Hawkins

I'm getting a chuckle out of all the different AAR standards, because
they don't exist.

I have before me a copy of a drawing titled:

4-C-40 TON STEEL SHEATHED BOXCAR
4-D-50 TON STEEL SHEATHED BOXCAR

GENERAL ARRANGEMENT

ASSOCIATION OF AMERICAN RAILROADS
MECHANICAL DIVISION

DATE APRIL 1,1937 PLATE No.1500-K

This 1937 drawing shows a boxcar with R-3-4 IDE ends, a diagonal panel
roof, and the improved Youngstown door. How can this be, you ask?
Simple, this is revision "K" of the 1937 drawing.

In reality, when the design was adopted in 1937, it became THE AAR
standard boxcar, and simply went through a gradual series of
incremental changes from that point on. The dates of the revisions on
this plate are as follows:

A 12/31/37
B 8/3/40
C 3/15/41
D 6/25/42
E 12/1/45
F 4/1/48
G 3/1/51
H 6/24/54
I 3/1/56
J 12/1/57

And finally K, 4/1/62. There may be more, but not on my copy of the
drawing.

Each and every one of these could be thought of as the AAR standard
boxcar of that particular date, or they could all be thought of as the
AAR 1937 standard boxcar, as revised. The only thing they are not is
the 1942 standard, or 1944 standard, or the Post War standard, except
in the most general terms. Those are just names that some modeler made
up somewhere along the line. In reality, we should be discussing the
"Revision C car", or the "Revision J car".

Do I know what changes were made to the standard at each revision?
Unfortunately not, as there is no revision notes included with the
drawings. But, that's no excuse for making up names to mask the lack
of knowledge. How about we just call the thing the AAR Standard
boxcar, with improved Dreadnaught ends and a diagonal panel roof, or
whatever, until we find out what the proper nomenclature should be?


Dennis