Re. the "War Babies" article in the RP CYC on wartime reefers for FGE, BRE and WFE

I noted that BRE reverted to tongue & groove for its next group of cars in 1944, and that plywood sided cars of all three companies requiring attention were re-sheathed with tongue & groove in the 1950's. Given the perceived advantages of the plywood in terms of cost, weight, ease of fabrication, etc. I am wondering why plywood wasn't retained for wood-sided cars. Longevity, or ease of repair?

Any suggestions?

Rupert Gamlen
Auckland NZ

Rupert Gamelin wrote:
"I noted that BRE reverted to tongue & groove for its next group of
cars in 1944, and that plywood sided cars of all three companies
requiring attention were re-sheathed with tongue & groove in the
1950's. Given the perceived advantages of the plywood in terms of
cost, weight, ease of fabrication, etc. I am wondering why plywood
wasn't retained for wood-sided cars. Longevity, or ease of repair?"

PFE used plywood in several classes of rebuilds, but chose to either
resheath the cars with tongue & groove siding. Plywood fared poorly
in service, tending to curl and opening the joints between sheets.
See p 145-148 of Thompson/Church/Jones' Pacific Fruit Express for more
details on PFE's experience with their R-30/40-24 plywod side
rebuilds. Other classes rebuilt with plywood sides are discussed in
Chapters 6 and 7.


Ben Hom

I noted that BRE reverted to tongue & groove for its next group of cars in 1944, and that plywood sided cars of all three companies requiring attention were re-sheathed with tongue & groove in the 1950's. Given the perceived advantages of the plywood in terms of cost, weight, ease of fabrication, etc. I am wondering why plywood wasn't retained for wood-sided cars. Longevity, or ease of repair?

As Ben Hom has already answered, the problem was in adequate sealing of the edges of the plywood sheets. Soo Line had the same problem with box cars having single sheathing of plywood. Rubber and metal seal strips were not good enough. The plywood curled and cracked, and was judged (by PFE anyway) to be inadequately weather resistant if any of the protection system (joint sealing strips, and paint generally) failed. PFE concluded it was not worth repairing them in kind, thus returned to T&G. As the Fruit Growers and PFE engineering people enjoyed a close and cooperative relationship, I'm sure the mutual experiences of each contributed to similar decisions.

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

Re. the "War Babies" article in the RP CYC on wartime reefers for FGE, BRE and WFE

" I am wondering why plywood wasn't retained for wood-sided cars. Longevity, or ease of repair?"

Thanks for these responses. If the curling and sealing problems manifested themselves within 2 years causing the BRE to revert to tongue & groove, and with plywood having been used in this manner from 1935 onwards, one wonders why plywood was used for these cars in the first place. Perhaps the designers thought they had solved the problems. Alternatively, they perceived the advantages to outweigh the potential problem.


Rupert Gamlen
Auckland NZ

Rupert Gamlen wrote:

Thanks for these responses. If the curling and sealing problems manifested
themselves within 2 years causing the BRE to revert to tongue & groove, and
with plywood having been used in this manner from 1935 onwards, one wonders
why plywood was used for these cars in the first place. Perhaps the
designers thought they had solved the problems. Alternatively, they
perceived the advantages to outweigh the potential problem.

Plywood was widely used in World War II and supposedly had been much improved. The "Douglas Fir Plywood Association" promoted it widely for many uses, from homebuilding to freight car exteriors (and interiors, where it was satisfactory). Perhaps the plywood of the late 1940s was no better than 1935, but evidently people thought it was.

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

--- In STMFC@..., Anthony Thompson <thompson@s...> wrote:

As Ben Hom has already answered, the problem was in adequate
sealing of the edges of the plywood sheets. Soo Line had the same
problem with box cars having single sheathing of plywood. Rubber and
metal seal strips were not good enough. The plywood curled and cracked,
and was judged (by PFE anyway) to be inadequately weather resistant if
any of the protection system (joint sealing strips, and paint
generally) failed. PFE concluded it was not worth repairing them in
kind, thus returned to T&G....

Tony,

Care to offer a citation to info on the Soo Line plywood covered boxcars? I suspect you are thinking of the GN, but I'm always looking for new and interesting facts about the Soo.

The Soo Line did cover quite a few cabooses with plywood in the late sixties and it held up well enough. The joints were covered with sheet metal lap strips that had a shallow bend in the center, which tended to keep the edges tight to the plywood between the screws. Then again, this "fix" was only intended to last five years, until sufficient new steel cabooses were on the property. The plywood was applied right over the ratty car siding, with a new wider letterboard applied to cover the top edge.

If I could hazard a guess as to what the railroads disliked about plywood on freight cars, it is plywood's tendency to shed paint in sheets. The hard early wood grain in Douglas fir is very resistant to paint penetration, and in making rotary cut veneer, the hard grain becomes wide bands. Plywood wasn't used for house siding, either, for the same reason until the industry came up with what is known as T-111 siding. This plywood has strips of rough sawn veneer on the face ply, which hold paint well, separated by grooves to make it look like boards. It came too late to be used on freight cars, and anyway, I can't see the car builders liking the rough
sawn look on a freight car.


Dennis Storzek
Big Rock, IL

Dennis Storzek wrote:

Care to offer a citation to info on the Soo Line plywood covered boxcars? I
suspect you are thinking of the GN, but I'm always looking for new and
interesting facts about the Soo.

There was a photo in Railway Age, I think in the late 1930s. I've recently been browsing the RA volumes looking for additional freight car stuff, but wasn't specifically interested in the Soo cars. If you want me to look back for a citation, I'll do so. The photo was one of the "Fowler" cars.

This plywood has
strips of rough sawn veneer on the face ply, which hold paint well,
separated by grooves to make it look like boards. It came too late to be
used on freight cars, and anyway, I can't see the car builders liking the rough
sawn look on a freight car.

Dennis, are you aware of the horizontally grooved plywood that PFE tried out? Photos in the book.

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

In Tony Thompson's message back to Ben he writes:

As Ben Hom has already answered, the problem was in adequate sealing of

the edges of the plywood sheets. Soo Line had the same problem with box cars
having single sheathing of plywood. Rubber and metal seal strips were not good
enough. The plywood curled and cracked, and was judged (by PFE anyway) to be
inadequately weather resistant if any of the protection system (joint
sealing strips, and paint generally) failed. PFE concluded it was not worth
repairing them in kind, thus returned to T&G....<<

Likely the issue was not a plywood (or also know as Plyscore at the time)
but actually an application error... but at the time there was likely little
know of the issue of application or were not properly relayed to the end user.
When you butt plywood edge to edge and don't leave a gap the aforementioned
condition results... apparent delamination at the edge, which could have been
avoided if properly applied. The sheets must be gapped or the top veneer
can't expand and that causes the top veneer to separate from the veneer below and
causes the top veneer to wrinkle or as Tony puts it "curled" or it may check
or as Tony puts it "cracks" These are all installation errors. While the
edges do need sealed to avoid true glue-line delamination I don't see that
condition in the effects of the plywood cabooses(NYC) or Reefers that were
sheathed with Douglas Fir Plywood. Now to see why the SOO Line cabooses didn't do
this...


Dennis writes...

Tony,

Care to offer a citation to info on the Soo Line plywood covered boxcars? I

suspect you are thinking of the GN, but I'm always looking for new and
interesting facts about the Soo.<

The Soo Line did cover quite a few cabooses with plywood in the late

sixties and it held up well enough. The joints were covered with sheet metal lap
strips that had a shallow bend in the center, which tended to keep the edges
tight to the plywood between the screws. Then again, this "fix" was only
intended to last five years, until sufficient new steel cabooses were on the
property. The plywood was applied right over the ratty car siding, with a new wider
letterboard applied to cover the top edge.<

Ah Ha! We see that the installation had changed and it was done correctly
allowing the veneers to float between what Dennis describes as, "The joints
were covered with sheet metal lap strips that had a shallow bend in the center,"
a simple matter of letting the panels stay apart...

If I could hazard a guess as to what the railroads disliked about plywood

on freight cars, it is plywood's tendency to shed paint in sheets. The hard
early wood grain in Douglas fir is very resistant to paint penetration, and in
making rotary cut veneer, the hard grain becomes wide bands.<

Well, the grain is a bit of an issue but the real reason that the paint
wouldn't hold is because the veneers were constantly moving, expanding and
contracting and yes the wide grain (flat grain) was an issue but the edge grain
could be even worst in reality. But if the plywood was primed with White
pigmented shellac the paint peel issue would have diminished for the most part...
But that primer is much more expensive as well...

Plywood wasn't used for house siding, either, for the same reason until the

industry came up with what is known as T-111 siding. This plywood has strips
of rough sawn veneer on the face ply, which hold paint well, separated by
grooves to make it look like boards. It came too late to be used on freight
cars, and anyway, I can't see the car builders liking the rough sawn look on a
freight car.

Dennis Storzek<

Dennis is correct, plywood was not used for house siding until much later
than this list chooses to cover. But the one of the first sidings used was 303
T-1-11 ( it was actually referred to as 303-0,6, or 18 meaning the number of
repairs, synthetic or natural, to the face) but at first with a smooth face
and then later with a resawn face which did hold paint better. The success of
the panel was and continues to be that the panels don't but tight together...
But I have seen some repainted wood sheathed cars that look to have been
rough sawn but is just shoddy restoration work...

Greg Martin

Greg Martin writes:
Likely the issue was not a plywood (or also know as Plyscore at the time)
but actually an application error... but at the time there was likely little
know of the issue of application or were not properly relayed to the end user.
When you butt plywood edge to edge and don't leave a gap the aforementioned
condition results... apparent delamination at the edge, which could have been
avoided if properly applied. The sheets must be gapped or the top veneer
can't expand and that causes the top veneer to separate from the veneer below and
causes the top veneer to wrinkle or as Tony puts it "curled" or it may check
or as Tony puts it "cracks" These are all installation errors.

I'm sure Greg is right. The PFE documents did refer to "curling, checking and cracking," but as it happens the shop sketch I saw did have about a 1/8 inch gap between the plywood sheets. Is that an inadequate gap, Greg? That gap was in addition to the T-section metal seal strip (with the "leg" of the T down between the sheets).
As for it being an "installation error," I have no doubt that PFE followed the instructions of the Douglas Fir Plywood Association --
whatever they may have been <g>.

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

--- In STMFC@..., Anthony Thompson <thompson@s...> wrote:

I'm sure Greg is right. The PFE documents did refer to "curling,
checking and cracking," but as it happens the shop sketch I saw did
have about a 1/8 inch gap between the plywood sheets. Is that an
inadequate gap, Greg? That gap was in addition to the T-section metal
seal strip (with the "leg" of the T down between the sheets).
As for it being an "installation error," I have no doubt that
PFE followed the instructions of the Douglas Fir Plywood Association --
whatever they may have been <g>.

Three possibilities come to mind. 1) the drawing calls for the 1/8" gap, but the shops mis-interpreted this as being the gap FOR the metal trim, rather than IN ADDITION TO it. 2) the shops installed the plywood with the specified gap, but the gap, while adequate for house construction, was inadequate for railroad service. 3) the sheets moved after installation due to the car frame twisting and "weaving", forcing the edges of the sheets together.

I am not aware that the Soo Line gave this any consideration when the recovered their cabooses, but then again, the plywood was so far from the car frame, being attached to the ild siding, that it likely just shifted towards the end of the car when it expanded from moisture.

I kind of wonder why the Ply-Metal Company didn't jump in here with their metal faced wood laminate. Ply-Metal was adopted early on by Electro-Motive for side sheets on F and E units, and seemed to give good service. I suppose the extra cost and weight made it non-competitive with plain steel.


Dennis Storzek

Dennis Storzek wrote:

Three possibilities come to mind . . . 3) the sheets moved after installation due
to the car frame twisting and "weaving", forcing the edges of the sheets
together.

In a steel-framed car? All of the PFE cars sheathed with plywood were of that type.

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

Tony writes...

"I'm sure Greg is right. The PFE documents did refer to "curling,
checking and cracking," but as it happens the shop sketch I saw did
have about a 1/8 inch gap between the plywood sheets. Is that an
inadequate gap, Greg? That gap was in addition to the T-section metal
seal strip (with the "leg" of the T down between the sheets).

"As for it being an "installation error," I have no doubt that
PFE followed the instructions of the Douglas Fir Plywood Association --
whatever they may have been <g>.

Tony Thompson"

Well, let's see we use and 1/8" gap and then we fill that gap with a piece of "TEE" section sheet metal and the gap was in addition to the width of the metal??? HMMM something doesn't add up and I wonder if it was as confusing to the shop crew as it is to this reader? So was the gap intended to be greater than 1/8", like say ¼" and then the metal? I can see that there might have been an installation issue, but the only way to be sure is look at the drawings, then compare that to the practice...It's diffecult to picture as the metal strip would have to "float" or the plywood would have to "float" the two couldn't be rigid UNLESS the gap was properly maitnained. Gone are the cars and the verifaction, regardless the experiment was not repeated by PFE.

If the veneers held across the panel and large sheets of veneer didn't come off it was not a production issue with the plywood. Generally, if there is an issue with a glue line on plywood it was done at a given point and restricted to a few sheets not a complete run or shift produced. But without the evidence we will never know for sure. Remember, these types of plywood panels were not made just for the railroads use but marine use or cooler/freezer use where moisture was constantly present and I can tell you they did last. Again, we would have to put all the pieces of the puzzle together to see what was the cause of the failure. As Dennis mentions perhap the experiment would have worked if the plywood was sheathed with a moisture resistant coating as a cover veneer like those used by sign painters(we call these overlays and they are usually resin soaked paper). These are commonly used today as concrete form and other uses. We certainly know more today about plywood then they did then and most application errors are avoided. This reads to me as an issue that was caused to the plywood when it was installedt that caused restricted expansion and the veneers buckled across the face veneers.

Greg Martin


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