Topics

Wood Roofs


byronrose@...
 

On Fri, 6 Apr 2001 09:30:06 -0700 (PDT) Tom Gloger <tomgloger@yahoo.com>
writes:


As far as I can make out, it all centers around the need for
water-tightness. All or nearly all boxcars and reefers had tight
boards and metal roofs by the late 1930s. Stock cars, OTOH, often
still had wood roofs (and thus didn't require lateral extensions to
the
running boards) because they were open to the weather anyway. (Am I
correct in assuming wood roofs were difficult to keep watertight?)

I don't think that weather tightness was ever a factor in what we see as
wood roofs on freight cars. Wood roofs were actually wood over a plastic
or metal waterproof membrane and required the wood for physical
protection. I believe it was the wood that created a maintenance
problem, i.e., rotting out because the water water was trapped in the
relatively flat (almost horizontal plane) joints unlike the joints in
vertical surfaces. That is what I feel caused the wholesale shift to
metal roofs after WW1. That's not to say that the membranes didn't cause
their share of problem, but wood roofs hung on for quite a few more
years.

Refrigerator cars continued to keep wood roofs because of the perception
of their being a better insulating and walking surface. Eventually, even
the larger reefer fleets saw the economies in all metal roofs with the
better insulating materials becoming available, and started switching by
the mid 30s. This was about the same time that the few stock cars being
built also switched to metal roofs, but new wood roof reefers were being
built thru WW2.

Of course, the PRR was the exception to all of the above. They started
using metal roofs a decade before WW1 but forgot to make them watertight.
Unfortunately, this carried over to a whole generation of steel box
cars, the X-29 clones, aka the unofficial 1924 ARA steel box cars, and
even the Pennsys own 1930s cars, the round roofs.

BSR
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Ed Workman <eworkman@...>
 

At 01:28 PM 4/6/01 -0400, you wrote:

. All or nearly all boxcars and reefers had tight
boards and metal roofs by the late 1930s.
Inside metal roofs were indiviual sheets supported by wood framing and covewred by wood sheathing : Winslow". This was considered an improvement over the "double board" wood rood in which the top course was staggered over grooves in the bottom course boards: Leaks thru the top joints were caught by the lower. The attempt to improve this roof was to put a membrane between the courses. That membrane was similar to today's roofing felt and was defeated by the constant racking of the car so that the sheathing rubbed holes thru it. Inside roofs were also defeated by the racking and twisting. "Plastic", until the 30's was taken to mean deformable rather than denote products we consider to be plastic these days. Thus, the non'wood roof members (steel, infrequently copper, felt) were not "membranes" in the true sense as there were many joints and seams, all subject to wear and failure

Outside metal roofs were supported on wood sheathing, then just by wood purlins held by metal carlines in the oughts, All metal flexible roofs appeared in the early teens. Racking and twisting of the carbody wore holes in these roofs too. Rigid all-steel roofs appeared also but were not typical until late 20's. Rigid steel roofs provided the ability to connect all the parts to achieve rigidity, and the resulting rigidity greatly reduced the constant distortions which had destroyed previous roof types.
Double board roofs continued to be installed on stock cars, since as you say, waterproofing was of little concern.

Boxcar roofs (and ends and doors) were of great concern by 1915. Roof leakage caused large claims for damaged lading. IIRC the Santa Fe went to the trouble of constructing sprinklers to test individual car roofs in order to try to assign leak free cars to high value loads and reduce the cost of claims


byronrose@...
 

On Fri, 6 Apr 2001 09:30:06 -0700 (PDT) Tom Gloger <tomgloger@yahoo.com>
writes:

Stock cars, OTOH, often
still had wood roofs (and thus didn't require lateral extensions to the
running boards) because they were open to the weather anyway. (Am I
correct in assuming wood roofs were difficult to keep watertight?)
Why would you assume that it's okay to keep a leaking roof on a stock
car? If you were shipping your prize cattle to market would you want
them to have water drizzling on them while they're traveling at 40-50
mph? If you go to the effort to build a roof, you also do what you have
to to keep it waterproof.

Yes, I know that they used to drive cattle by land with no weather
protection, and they also lost 10-20% of body weight on the trip. That's
why stock cars were so highly valued in the "old west" and towns fought
to get railroads.

But as I pointed out earlier, reefers were being built with wood roofs
even later than stock cars and there's probably nothing that needs to be
kept more watertight than insulation in a reefer.

BSR
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Garth G. Groff <ggg9y@...>
 

Byron,

As I'm sure you know, many stock cars were built with the same types of
steel roofs as boxcars. Still, there were a lot of stock cars that
retained their wooden roofs right up into the 1950s. I suggest that many
roads had little incentive to improve these cars, or replace them with
more modern ones. Stock car use was often seasonal, or tended to have
unprofitable empty back hauls, and so there was a smaller return on
investment for any improvements. No wonder railroads gave up this
traffic to trucks so easily.

Kind regards,


Garth G. Groff

Tom wrote:

Stock cars, OTOH, often
still had wood roofs (and thus didn't require lateral extensions to the
running boards) because they were open to the weather anyway. (Am I
correct in assuming wood roofs were difficult to keep watertight?)


Dave & Libby Nelson <muskoka@...>
 

Yes, I know that they used to drive cattle by land with no weather
protection, and they also lost 10-20% of body weight on the trip. That's
why stock cars were so highly valued in the "old west" and towns fought
to get railroads.
Somewhere here in the house I've got a copy of _The Essentials of Livestock
Marketing_, a mid-50's propganda piece from some committee representing
stockyard companies, but I can't put my hand on it right now. They assert
livestock will lose a good percentage of it's weight in transit on any
vehicle (I seem to remember them citing a 5-10% loss) -- weight that'll go
back on at the stockyards own feedlot (for a fee).

I'd imagine the value of stock cars to the "old west" was in the geographic
fact of in-use farmland between range and consumer (i.e., the drive door was
barred).

Dave Nelson