Re: Plywood reefers

Dennis Storzek <dstorzek@...>

--- 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....

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

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