Dave Nelson, the Master of STMFC Statistics, sent me some interesting info
the other day.

The data shows that in 1955, wheat, corn, and sorghum were loaded at an
average of 54 tons per car.

Before you start yawning, realize that this leads to some interesting
conclusions, if my assumptions are correct.

Assumption 1: Cars are either 50-ton or 70-ton capy. There's no such
thing as a 55-ton or 60-ton car. (Right?)

Assumption 2: LO's were 70-ton capy cars in 1955 (don't have my ORER handy
to check).

Assumption 3: Box cars were 50-ton capy cars in 1955. (Where there many
70-ton boxes at that time?)

If Assumption 1 holds, then a little bit of math tells us that 80% of the
cars that carried wheat were 50-ton cars, and the other 20% were 70-ton
cars.

If all three Assumptions are true, then we know that 20% of the wheat
traveled in LO's. Furthermore, if one looks up data for various years, we
can see how quickly the grain industry moved from box cars to covered
hoppers.


For those of you not modeling granger roads, one can probably make similar
interesting inferences from other commodities (e.g. Anthracite Coal at 57
tons / car; or Pig Iron at 58 tons / car).

Regards,

-Jeff

--
Jeff Aley, Development Engineer jaley@...
Graphics Components Division
Intel Corporation, Folsom, CA
(916) 356-3533

Good reasoning Jeff, very logical. But possibly wrong, since a 50 ton car's
"capacity" was typically below the same car's "load limit". I'm sure that the
elevators tried to jam as much as possible into every car load, just keeping
below the load limit. I'd be VERY surprised if more than 5% of grain in 1955
was carried in LO's. It probably was much less than that.

Tim,

Thanks for pointing out the capy vs load limit; that's why I
posted my assumptions to the List.
I guess I'm still a little bit fuzzy on the "50-ton" rating. I
was under the impression that 50-tons comes from the trucks, and on
further reflection should be the weight of the car + load.
If that's true, then the weight of the load (wheat) is LESS than
50 tons (?).

If that's the case, then MORE (a greater percentage of the cars)
would have to be LO's to make the 54 ton "average". [I'm assuming that
the ICC tonnage data indicates weight of the load alone].

Am I misunderstanding the various weights? If so, please help me
out.

Thanks,

-Jeff


On Apr 30, 2:28pm, Tim O'Connor wrote:

Subject: Re: [STMFC] Car capy and LO's
Good reasoning Jeff, very logical. But possibly wrong, since a 50 ton

car's

"capacity" was typically below the same car's "load limit". I'm sure

that the

elevators tried to jam as much as possible into every car load, just

keeping

below the load limit. I'd be VERY surprised if more than 5% of grain in

1955

was carried in LO's. It probably was much less than that.

----- Original Message -----
From: Jeff Aley - GCD PE <jaley@...>

Assumption 1: Cars are either 50-ton or 70-ton capy. There's no such
thing as a 55-ton or 60-ton car. (Right?)
Assumption 3: Box cars were 50-ton capy cars in 1955. (Where there

many

70-ton boxes at that time?)

If Assumption 1 holds, then a little bit of math tells us that 80% of

the

cars that carried wheat were 50-ton cars, and the other 20% were

70-ton

cars.

If all three Assumptions are true, then we know that 20% of the wheat
traveled in LO's.

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-- End of excerpt from Tim O'Connor

--
Jeff Aley, Development Engineer jaley@...
Graphics Components Division
Intel Corporation, Folsom, CA
(916) 356-3533

Jeff Aley writes:

I guess I'm still a little bit fuzzy on the "50-ton" rating. I
was under the impression that 50-tons comes from the trucks, and on
further reflection should be the weight of the car + load.
If that's true, then the weight of the load (wheat) is LESS than
50 tons (?).

I am certain that I should stay away from this sort of thing and concentrate
on more straight
forward stuff like why the number of driving axles on a steam engine has
nothing to do with traction or what is the purpose of the third truck on a
shay, but, what the hell.

It all depends on the car. A 40 ft box car with 50 ton code D trucks might
have a capacity of 100,000 lbs. However, the allowable weight on the rails
is the light weight plus the load limit which must add to 169,000 lbs [ in
'54 ]. In the case of the PS-1 this might be 44500 + 124500= 169000 lbs. The
max weight of the stuff carried is 62.4 tons. All this assumes AAR or
Alternate Standard tubular axles on the trucks. This also assumes that no
little "*" is sitting there next to load limit.

Now, why put Capacity on the car if it can be exceeded? How should I know?
For guys that work for Intel or even NASA, this might be puzzling. At least
it is to me. I mean, if the load limit says 124500 lbs, I can usually tell
that the car can carry 62 tons of stuff without breaking in two.
I now bow to our more learned frt car gurus and learn about this
oddity...again. Meantime, if any of you want to discuss the slipping of
drivers or what that third truck on the Shay is doing back there...feel
free.

Oh. Jeff, you must get an ORER.

Mike Brock......Hmmm. Wonder how far out on this ice I can walk without
falling in. Let's see. Hmmm.....

Jeff Aley - GCD PE <jaley@...> wrote:

Assumption 1: Cars are either 50-ton or 70-ton capy. There's no such
thing as a 55-ton or 60-ton car. (Right?)

Almost all NYC 40-ft all-steel box cars were rated 55-ton capacity.

---------------------------------------------------------------
Jeff English Troy, New York
Proto:64 Classic Era Railroad Modeling
englij@...

| R U T L A N D R A I L R O A D |
Route of the Whippet
---------------------------------------------------------------

"Mike Brock" <brockm@...> wrote:

Now, why put Capacity on the car if it can be exceeded? How should I know?
For guys that work for Intel or even NASA, this might be puzzling. At
least it is to me. I mean, if the load limit says 124500 lbs, I can
usually tell that the car can carry 62 tons of stuff without breaking in
two.

1) The capacity is a nominal rating which allows car clerks and
shippers to quickly ascertain whether a given car is suitable for the
order of magnitude of their intended shipment. The load limit is the
absolute limit and is used after loading the car to compare the car's
total weight on the scale to the allowable weight. Now, not that
many cars were actually weighed, but a shipper could get into hot
water if they released an overloaded car.

2) The load bearing capacity of a car is not determined by the
structural engineering of its carbody but by the size of the journal
bearings. Apparently carbody structure is predicated by other
considerations that place its load-bearing capability far above that
of the bearings. Among those other considerations are the AAR
requirement to withstand a static 800,000-lb compressive force
through the center sill. Also probably the fatigue factor over a 40-
year life calls for an extremely robust structure. For the above
reasons, there is no probability that an overloaded car would break
in two.
Moreover, a car's capacity and load limit can be changed by
simply rolling different trucks under it, with absolutely no other
alterations. The RRs did exactly this fairly often.

---------------------------------------------------------------
Jeff English Troy, New York
Proto:64 Classic Era Railroad Modeling
englij@...

| R U T L A N D R A I L R O A D |
Route of the Whippet
---------------------------------------------------------------

Moreover, a car's capacity and load limit can be changed by
simply rolling different trucks under it, with absolutely no other
alterations. The RRs did exactly this fairly often.

Well, yes and no. Jeff is certainly correct that the size of the truck
journals was the primary factor in determining nominal capacity. However,
the AAR specs for the standard steel box cars were different for forty and
fifty ton versions, with the fifty ton cars having somewhat heftier center
sills and some other components, and this was also true of the earlier ARA
standard designs. This may, as Jeff suggests, have had more to do with
over-engineering the cars to compensate for wear and tear, etc. but just
putting 50 ton trucks under a 40 ton AAR standard box car didn't make it a
50 ton car.

Richard H. Hendrickson
Ashland, Oregon 97520

In a message dated 4/30/01 12:49:51 PM Pacific Daylight Time,
brockm@... writes:

<< Now, why put Capacity on the car if it can be exceeded? How should I know?

Mike,

The nominal capacity was stenciled on freight cars which corresponded to the
listings in the ORER. It would have been impossible to print all "true"
capacities in the ORER though for many years various railroad entries noted
the allowance of loading 10% higher than the nominal capacity. As the axle
loading increased the AAR mandated the additional LD LMT stencil. This
allowed shippers to know the actual loading capacity of an individual freight
car.


Regards,

Guy Wilber
Sparks, Nevada

Thanks to Tim, Mike, and the gang for educating me on capy.

I guess it all boils down to the fact that my "assumption 1" was wrong, so
my conclusions were similarly flawed. This just goes to show you that
there are three kinds of lies: lies, damned lies, and statistics!

Regards,

-Jeff



On Apr 30, 3:32pm, Mike Brock wrote:

Subject: Re: [STMFC] Car capy and LO's
Jeff Aley writes:

I guess I'm still a little bit fuzzy on the "50-ton" rating. I
was under the impression that 50-tons comes from the trucks, and on
further reflection should be the weight of the car + load.
If that's true, then the weight of the load (wheat) is LESS than
50 tons (?).

I am certain that I should stay away from this sort of thing and

concentrate

on more straight
forward stuff like why the number of driving axles on a steam engine has
nothing to do with traction or what is the purpose of the third truck on

a

shay, but, what the hell.

It all depends on the car. A 40 ft box car with 50 ton code D trucks

might

have a capacity of 100,000 lbs. However, the allowable weight on the

rails

is the light weight plus the load limit which must add to 169,000 lbs [

in

'54 ]. In the case of the PS-1 this might be 44500 + 124500= 169000 lbs.

The

max weight of the stuff carried is 62.4 tons. All this assumes AAR or
Alternate Standard tubular axles on the trucks. This also assumes that

no

little "*" is sitting there next to load limit.

Now, why put Capacity on the car if it can be exceeded? How should I

know?

For guys that work for Intel or even NASA, this might be puzzling. At

least

it is to me. I mean, if the load limit says 124500 lbs, I can usually

tell

that the car can carry 62 tons of stuff without breaking in two.
I now bow to our more learned frt car gurus and learn about this
oddity...again. Meantime, if any of you want to discuss the slipping of
drivers or what that third truck on the Shay is doing back there...feel
free.

Oh. Jeff, you must get an ORER.

Mike Brock......Hmmm. Wonder how far out on this ice I can walk without
falling in. Let's see. Hmmm.....




To unsubscribe from this group, send an email to:
STMFC-unsubscribe@...



Your use of Yahoo! Groups is subject to

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-- End of excerpt from Mike Brock

--
Jeff Aley, Development Engineer jaley@...
Graphics Components Division
Intel Corporation, Folsom, CA
(916) 356-3533

In a message dated 4/30/01 12:49:51 PM Pacific Daylight Time,
brockm@... writes:

<< Now, why put Capacity on the car if it can be exceeded? How should I know?

Mike,

The nominal capacity was stenciled on freight cars which corresponded to the
listings in the ORER. It would have been impossible to print all "true"
capacities in the ORER though for many years various railroad entries noted
the allowance of loading 10% higher than the nominal capacity. As the axle
loading increased the AAR mandated the additional LD LMT stencil. This
allowed shippers to know the actual loading capacity of an individual freight
car.


Regards,

Guy Wilber
Sparks, Nevada