--- In STMFC@..., "Gatwood, Elden J SAD "
<elden.j.gatwood@...> wrote:

Oh, I also wrote a multi-piece article on what I did for my

timeframe and

locale, in TKM, and there was only one person even vaguely

interested. I

think I could have better spent my time (hundreds of hours) building

more

models!

Elden Gatwood

Elden,

I read your article, and Bruce's, on car distribution and found it
informative, especially in the area of what to consider when analyzing
the issue. It is a tough subject to cover - I'm planning a layout
focused on WWII and the main line, with branches that primarily served
coal mines. Therefore the specific information in your article does
not directly apply to my situation, but the process you went through
was educational. So that makes at least 2 who found it helpful. I'm
sure there must be more, so please do not dispair!

I hope to do some XM distribution analysis of the Potomac yard data in
the group files since that was a PRR interchange point and may provide
some insight into the issue, even though it is a few years late for me.

Regards,
Dave Evans

--- In STMFC@..., "Malcolm Laughlin" <mlaughlinnyc@...>
wrote:

CN did a systemwide 8 AM check in the era of STMFC.

Steve Lucas.

--- In STMFC@..., Larry Jackman <Ljack70117@> wrote:

At 6 AM each morning the entire yard was check and recorded on a

special form. Two copies were sent to the accounting department

and

two copies to the car department and one filed in the files where
they were recorded.

This was done on the whole RR and was done on The Un Pac and John
Santa Fe.

It is of my opinion that this was done on every RR
in the good old US of A, So at 6 AM every freight car
in the good old US of A was on record.

I know for certain that it was not done on the NYC, MILW, NS or

B&M.

The UP and ATSF were rather wealthy railroads, from long haul
revenue, and in the 60's were not known for keeping a sharp eye on
costs.

So they not only needed to be known, they were known.

That it was done does not tell us that it was needed. It sounds

like

a want on the part of some official to give the car accounting
department a means for cross checking the data received from
interchange reports and wheel reports. Whether the costs saved by
having that cross reference exceeded the cost of all those yard

clerk

hours is an interesting question.

Yes, Jack you are correct and those records for all railroads were forwarded to the car accounting offices. Most of the per diem was a paper exchange, but not all of it.

Not sure what you mean by this. All per diem was netted every month between every pair of railroads and money was exchanged. Except for the extremely inprobable event that two railroads had equla numbers of days of the other's cars for a month.

> Then of course there were the privately owned cars that were due their share as well.
Greg Martin
--------------------------------------

Privately owned cars were a very different thing. There was nothing analogous to the per diem settlement. Each railroad paid the owner of each car. For per diem, the critical document was the interchange report. For mileage cars the key accounting source document was the wheel report.


Malcolm Laughlin, Editor 617-489-4383
New England Rail Shipper Directories
19 Holden Road, Belmont, MA 02478

--- In STMFC@..., Larry Jackman <Ljack70117@...> wrote:

At 6 AM each morning the entire yard was check and recorded on a

special form. Two copies were sent to the accounting department and
two copies to the car department and one filed in the files where
they were recorded.

This was done on the whole RR and was done on The Un Pac and John
Santa Fe.

It is of my opinion that this was done on every RR
in the good old US of A, So at 6 AM every freight car
in the good old US of A was on record.

I know for certain that it was not done on the NYC, MILW, NS or B&M.
The UP and ATSF were rather wealthy railroads, from long haul
revenue, and in the 60's were not known for keeping a sharp eye on
costs.

So they not only needed to be known, they were known.

That it was done does not tell us that it was needed. It sounds like
a want on the part of some official to give the car accounting
department a means for cross checking the data received from
interchange reports and wheel reports. Whether the costs saved by
having that cross reference exceeded the cost of all those yard clerk
hours is an interesting question.

It's a bit of a relief to read this e-mail tonight!

I was starting to wonder about the proportions of railway specific freight car books in my collection. Do I have enough PRR, or NKP or ATSF or ..... gee, I wonder how many of you have an over representation of books on the Canadian freight car fleet? Come to think of it, it seems I may need something SP.....

Rob Kirkham (tongue in cheek)


From: Dennis Storzek

--- In STMFC@..., "Mike Brock" <brockm@...> wrote:

Actually I said:

"The model that I prefer is a modified Nelson/Gilbert model which

states

that
RRs with "significant interchange" should have from 2 to 2.5 times the
national %."

I'm sure this is the key. [snip]...

But why bother? Data for the average railroad is only going to be good
for someone who freelances, but even then you run into the problem
that if you model the Maumee, what the heck is the Wabash hauling if
all that traffic is on the Maumee? Even if you get what was actually
happening right, you then have to modify it again to take into account
the new player you added.

I personally think that time would be better spent studying the
prototype one is trying to model, identifying the consists of the
trains as best one can from consists, interchange statistics, photos,
movies, whatever is available, noting not only the overall car mix,
but specific instances of heavy concentrations, because those heavy
concentrations aren't random events, they MEAN something, and modeling
them helps to capture the feel of the prototype.

Dennis

Dennis,I am in the process of a thorough study for a whole month for the
road that I am modeling.I am fortunate enough to have a relatively large
collection of wheel reports covering a period from 1942 to 1953.I personally
feel that the size and location of the road detirmines the traffic
pattern.We should also consider the time of the year and the size of the
sample being used.The proximity to Canada also must be considered in the
mix.Train # 9 has more Canadian box cars than any of the top 4 or 5 American
roads in the number of cars.Looking at loads actually carried show more
agricultural oriented products than industrial.Obviously the mix would not
be the same for a road in a heavily industrial area.While there have been
suggested other models for the mix,I choose to buy cars that I can verify
having been on the road for the period.A wheel report in one hand and an
ORER in the other provide me with the information I need before I make a
purchase Armand Premo

Amen, Richard and Dennis. What I was trying to say all along. This should satisfy everyone who has a dog in this hunt, recognizing each perspective as part of the whole, but not THE whole, makes sense, but probably won't.

John Stokes
Bellevue, WA



To: STMFC@...: rhendrickson@...: Thu, 21 Aug 2008 15:27:11 -0700Subject: Re: ADMIN: Re: [STMFC] Re: Freight car distribution




On Aug 21, 2008, at 1:13 PM, Dennis Storzek wrote:> [snip]> I personally think that time would be better spent studying the> prototype one is trying to model, identifying the consists of the> trains as best one can from consists, interchange statistics, photos,> movies, whatever is available, noting not only the overall car mix,> but specific instances of heavy concentrations, because those heavy> concentrations aren't random events, they MEAN something, and modeling> them helps to capture the feel of the prototype.>Bang on, Dennis. Thank you for stating so succinctly the case for researching the intended prototype intensively rather than getting absorbed in abstract statistics. Not to say that the statistics aren't enlightening, and that we shouldn't be grateful to those whose research made them available. However, they're not especially useful to a modeler, and may even be seriously misleading, until interpreted in the light of everything else that can be learned about the traffic on a particular RR at a particular place and time. I (and, I suspect, many others on this list) would be relieved if this turned out to be the last word on this subject, though I suspect that's too much to hope for.Richard Hendrickson

On Aug 21, 2008, at 1:13 PM, Dennis Storzek wrote:

[snip]

I personally think that time would be better spent studying the
prototype one is trying to model, identifying the consists of the
trains as best one can from consists, interchange statistics, photos,
movies, whatever is available, noting not only the overall car mix,
but specific instances of heavy concentrations, because those heavy
concentrations aren't random events, they MEAN something, and modeling
them helps to capture the feel of the prototype.

Bang on, Dennis. Thank you for stating so succinctly the case for
researching the intended prototype intensively rather than getting
absorbed in abstract statistics. Not to say that the statistics
aren't enlightening, and that we shouldn't be grateful to those whose
research made them available. However, they're not especially useful
to a modeler, and may even be seriously misleading, until interpreted
in the light of everything else that can be learned about the traffic
on a particular RR at a particular place and time. I (and, I
suspect, many others on this list) would be relieved if this turned
out to be the last word on this subject, though I suspect that's too
much to hope for.

Richard Hendrickson

--- In STMFC@..., "Mike Brock" <brockm@...> wrote:

Laramie Larry writes: (A friend of mine who has lived in Laramie
all his life - in particular the 1940s and 50s - describes these

cars as a "transfer run".)"

Meaning what? While I do not know for certain the location, the

train is a

4000 class [ Big Boy ] and a water tank is visible in 1953. The

locomotive

and date confines the train to the area between Green River and

Cheyenne. My

guess is that the location is Buford [ that vacation spa on the

east side of

Sherman Hill ]. I do not know the direction of travel.

Incidentally, the

first car is, I believe, a covered hopper followed by 36 reefers

followed by

the 36 SP box cars with a few others.> Mike Brock

I'm pretty certain the location is Speer and the train pulled by 4005
is westbound on track 3, which would have brought it through
Laramie. Incidentally, the water tower and some of the white
buildings are still there.

I'll ask my friend to define "transfer run" the next time I see him.

Best wishes,
Larry Ostresh
Laramie, Wyoming

--- In STMFC@..., "Mike Brock" <brockm@...> wrote:

Actually I said:

"The model that I prefer is a modified Nelson/Gilbert model which

states

that
RRs with "significant interchange" should have from 2 to 2.5 times the
national %."

I'm sure this is the key… I'm sure that after one applies a whole
bunch of "weighting factors" that account for proximity of other
roads, preferred interchange partners, preferred routes for "rollers",
etc, the little bit of traffic that's left will look quite similar to
the Gilbert / Nelson proportions. The problem is, those weighting
factors are going to be different for every stretch of railroad one
could possibly model. As examples, compare the Yosemite Valley, which
had almost no cars of its own, with the similar sized Greater Winnipeg
Water Works District Railway, which had, as far as I know, no reason
to handle a foreign car, since the line basically functioned as a
conduit to bring gravel from pits along the line into the city for use
by the local construction industry.

I would suspect that the closest to the "average" stretch of railroad
would be the NKP or Wabash; railroads smack dab in the middle of the
country that handled the largest proportion of overhead traffic vs.
loads originating and terminating on line. If one had good train
consists for those lines, perhaps that would be the place to start
trying to determine correction factors for proximity and connections
of the "average" railroad.

But why bother? Data for the average railroad is only going to be good
for someone who freelances, but even then you run into the problem
that if you model the Maumee, what the heck is the Wabash hauling if
all that traffic is on the Maumee? Even if you get what was actually
happening right, you then have to modify it again to take into account
the new player you added.

I personally think that time would be better spent studying the
prototype one is trying to model, identifying the consists of the
trains as best one can from consists, interchange statistics, photos,
movies, whatever is available, noting not only the overall car mix,
but specific instances of heavy concentrations, because those heavy
concentrations aren't random events, they MEAN something, and modeling
them helps to capture the feel of the prototype.

Dennis

Laramie Larry writes:

"Or maybe not: It turns out that the probability of 36 or more cars
is so low that Excel cannot calculate it. For example a 90 boxcar
train with a "mere" 20 or more SP boxcars would occur only once in
every 19.5 billion trains. Conclusion: This train could not have
occurred by chance alone. (A friend of mine who has lived in Laramie
all his life - in particular the 1940s and 50s - describes these cars
as a "transfer run".)"

Meaning what? While I do not know for certain the location, the train is a 4000 class [ Big Boy ] and a water tank is visible in 1953. The locomotive and date confines the train to the area between Green River and Cheyenne. My guess is that the location is Buford [ that vacation spa on the east side of Sherman Hill ]. I do not know the direction of travel. Incidentally, the first car is, I believe, a covered hopper followed by 36 reefers followed by the 36 SP box cars with a few others.

"Suppose that the 4% number is wrong; Tim Gilbert's data lists 4.9% SP-
Pac ownership in 1956".

Except that in 1953 the number should be 4.35% for 1953...assuming halfway between 52's 4.2% and '54's 4.5%.

"Let's be generous and make it 5%. Then a 90
car train would have 20 or more SP boxcars once in every 356 million
trains. (Tim's data are at "4060totalboxcarsUSownership.xls" in the
files section of this list.)

Rather than using the proportion of the national fleet, how about
giving more "weight" to SP cars on the UP because of the "connection"
between the two railroads, or because of nearness or whatever? Let's
say we "weight" the SP cars by a factor of two (Mike Brock suggests a
weight of 1.5)."

Actually I said:

"The model that I prefer is a modified Nelson/Gilbert model which states that
RRs with "significant interchange" should have from 2 to 2.5 times the
national %."

I may have said 1.5 at some point...

"To apply the desired weight, multiply it by the
national proportion: e.g., 2 * 5% = 10%. Using a "probability of
success on each trial" of 10% and a 90 boxcar train we find that
Excel still cannot calculate it because the probability is too low (a
train with "only" 30 or more SP boxcars would occur once every 3
billion trains). Conclusion: No reasonable weighting will reproduce
the train actually observed - we must reject the null hypothesis.
That is, the observed train composition is not the result of chance
alone."

My feeling as well. And, I notice the same thing with trains that are easier to identify...lumber laden eastbounds with 31 SP box cars for example.

Mike Brock

Hi Folks

A week or so ago I posted a message about a "random train" Excel
spreadsheet I had created, and gave three examples of its output
(message #75066). Briefly, the spreadsheet generates a list of 40
boxcars chosen at random from a universe of cars which approximates
the U.S. boxcar fleet ownership in 1949. Experienced Excel users can
adapt the spreadsheet to create random trains of any desired length
using whatever universe they would like.

In message #75229 I described how I automated the spreadsheet by
running it 100,000 times. That is, it created 100,000 randomly
generated car lists, with 40 cars per list. The main purpose of this
simulation was to test whether the random train spreadsheet was
operating correctly; if it was, then over the long run, the average
proportions of the randomly generated cars should tend to the
proportions of the universe (they did). The simulation also recorded
the maximum number of cars generated during any of the 100,000
iterations (for each road). For example, the number of NYC cars in
the three lists in message #75066 was 4, 1 and 6. During the
simulation, there was at least one car list with 14 NYC cars. (In a
list of 40 cars that is proportional to 1949 national averages, one
should expect 4 from the NYC.)

Subsequently, I have refined the simulation so as to record the
entire distribution of cars for each road during a simulation of
100,000 car lists. For example, the national proportion of New Haven
boxcars was less than 1% in 1949; most random trains of 40 cars would
not have any NH cars, but sometimes there will be one or more. The
next list shows the frequency distribution of 0, 1, 2, … NH cars
generated by the simulation of 100,000 car lists (71,508 car lists
had 0 NH cars; 24,068 had 1 NH car, etc.):

0___71,508
1___24,068
2___3,963
3___421
4___37
5___3
These numbers can be converted to probabilities by dividing by
100,000. Thus the probability of a car list with 40 cars and none
from the NH is .715, 1 car = .241, 2 cars = .040, etc.

After examining the results of this simulation, it seemed to me that
the process of random car selection was much like the ball and urn
models I had learned about in my statistics classes umpteen years
ago: An urn has some red and white balls of a known proportion.
Reach in and grab a ball; if red, then record it as a "success", and
if white as a "failure"; replace the ball then repeat the process for
a certain number of times, say 40. What is the probability of 0
successes? Exactly 1 success? Exactly 2, 3, … ? These
probabilities are given by the binomial distribution. The next list
shows the binomial distribution for 0, 1, 2, … (multiplied by
100,000) for 40 trials and a "probability of success on each
trial".0084 = .84% (this is the national proportion of NH boxcars in
1949 that I used for my simulation).
0___71,483
1___24,098
2___3,960
3___423
4___33
5___2

Note the close correspondence of the simulation and the binomial
distributions in the two lists. This and the examination of other
simulation results convinced me that my process of random car
selection could be effectively modeled by the binomial distribution
(I also compared the Poisson distribution). If anyone would like a
copy of my simulation results, contact me off list.

To use the binomial distribution, all you need to specify is the
number of trials (read boxcars in a train) and the probability of
success on each trial (read proportion of cars of a particular
ownership or type). The proportions of cars can be national,
regional, or any other proportion you wish to use. You can make the
calculations with the aid of tables, programs such as Excel, or any
of several on-line calculators.

I should point out a key difference between my simulation model and
the real world: Just like cards, a train "has memory". This means
that once a car is removed from the population and placed in the
train, it cannot be placed again in the same train. Once the first
NH car is chosen with a probability of success on each trial of
6,012 / 719,349 (NH boxcars divided by national boxcars, 1949) the
probability of success on each trial for the next one changes to
6,011 / 719,348. This is the difference between sampling with
replacement (my simulation) and sampling without replacement (real
world). The binomial distribution also assumes sampling with
replacement.

One use for the binomial distribution is to test real world examples
for randomness. Again reaching back many years to my statistics
classes, I am reminded of the "null hypothesis": A researcher
discovers something interesting and suspects it is not merely
random. The null hypothesis is that it IS random, while the
alternative hypothesis is that it is not. The null hypothesis is
assumed to be true unless the researcher is 95% or 99% confident that
it is false (these are typical confidence levels).

The UP train with the large number of SP boxcars is an example. My
understanding is that this train had some 90 boxcars, 36 of which
were SP. In order to calculate the binomial distribution, we need to
know the number of "trials" (i.e., cars in the train, say 90) and
the "probability of success on each trial" (i.e., the proportion of
SP cars in the national fleet, say 4% = .04). From this you can find
the probability of a train with exactly 0, 1, 2, …, 36, … SP cars.

Or maybe not: It turns out that the probability of 36 or more cars
is so low that Excel cannot calculate it. For example a 90 boxcar
train with a "mere" 20 or more SP boxcars would occur only once in
every 19.5 billion trains. Conclusion: This train could not have
occurred by chance alone. (A friend of mine who has lived in Laramie
all his life – in particular the 1940s and 50s – describes these cars
as a "transfer run".)

Suppose that the 4% number is wrong; Tim Gilbert's data lists 4.9% SP-
Pac ownership in 1956. Let's be generous and make it 5%. Then a 90
car train would have 20 or more SP boxcars once in every 356 million
trains. (Tim's data are at "4060totalboxcarsUSownership.xls" in the
files section of this list.)

Rather than using the proportion of the national fleet, how about
giving more "weight" to SP cars on the UP because of the "connection"
between the two railroads, or because of nearness or whatever? Let's
say we "weight" the SP cars by a factor of two (Mike Brock suggests a
weight of 1.5). To apply the desired weight, multiply it by the
national proportion: e.g., 2 * 5% = 10%. Using a "probability of
success on each trial" of 10% and a 90 boxcar train we find that
Excel still cannot calculate it because the probability is too low (a
train with "only" 30 or more SP boxcars would occur once every 3
billion trains). Conclusion: No reasonable weighting will reproduce
the train actually observed – we must reject the null hypothesis.
That is, the observed train composition is not the result of chance
alone.

I suspect that if we begin applying the binomial distribution to real
world data we will find many cases in which we should reject the null
hypothesis of random car assignment. This does not imply that the
random assignment model should be ignored, of course; it simply means
that other factors (real world consists, photos, personal choice,
etc.) should also be considered. For example, we may find cases such
as transfer runs or large shippers where it makes sense to treat
blocks of cars as a unit and to assign these blocks, rather than the
individual cars, to trains.

Best wishes,
Larry Ostresh
Laramie, Wyoming

John Stokes wrote:

Which is well and good to know, but where are all those mountains of reports now when we need them?

They're up at high altitude, helping warm the planet <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

Which is well and good to know, but where are all those mountains of reports now when we need them?

John Stokes
Bellevue, WA



[Non-text portions of this message have been removed]

At 6 AM each morning the entire yard was check and recorded on a
special form. Two copies were sent to the accounting department and
two copies to the car department and one filed in the files where
they were recorded. This was done on the whole RR and was done on The
Un Pac and John Santa Fe. It is of my opinion that this was done on
every RR in the good old US of A, So at 6 AM every freight car in the
good old US of A was on record. So they not only needed to be known,
they were known.
Thank you
Larry Jackman
ljack70117@...

Yes, Jack you are correct and those records for all railroads were forwarded to the car accounting offices. Most of the per diem was a paper exchange, but not all of it. Then of course there were the privately owned cars that were due their share as well.

Greg Martin

In a message dated 8/19/2008 10:21:16 P.M. Eastern Daylight Time,
mlaughlinnyc@... writes:

There are no data sets that truly support either model. Because railroads
didn’t keep counts of foreign cars on line by ownership, the necessary data
sets probably never existed. So the choice is between



I would suggest that this data was collected to some extent by the
accounting departments. How else would they determine the per diem payments to the
various roads. Yes, I recognize that per deims were frequently offset by Road
A with what Road B owed Road A and only the balance actually paid. But
nevertheless the number of cars on property each day needed to be known.

Rich Orr



**************It's only a deal if it's where you want to go. Find your travel
deal here.
(http://information.travel.aol.com/deals?ncid=aoltrv00050000000047)


[Non-text portions of this message have been removed]

But wouldn't that information be needed every day to pay for per diem

charges? Jack Burgess

Yes, on the PRR at least, each interchange point had a record (I have some)
of cars set-out and received, and the time, and that data was assembled for
forwarding to the finance offices for payment of per diem charges. Units
train blocks were provided in sum on that same sheet.

I had the opportunity to go through numerous indexes at the PRR archives
earlier this year, and was, as always, unable to find any of this
information.

I have been told many times that the Business Management folks in the PRR
kept many of these records, for use in business planning, which seems
obvious. But, they also destroyed the raw data (at some location), from what
I was told, since that data would be a valuable tool to competitors, or if in
the wrong hands, could be used to influence stock prices, if assembled
correctly. That was why train consists were destroyed, and why us PRR guys
have only few examples.

If the PRR had a policy of destroying lists of who got what, how much, and
when, we may never be able to answer some of these questions.

Oh, I also wrote a multi-piece article on what I did for my timeframe and
locale, in TKM, and there was only one person even vaguely interested. I
think I could have better spent my time (hundreds of hours) building more
models!

Elden Gatwood

No question of the feasibility of this kind of report for a
small railroad. What was the total number of cars on line Jack ?
In the case of the YV, it would have been easy to keep such a
record just from the single daily interchange report that had all
cars coming on the railroad for that day.

In contrast, consider a railroad such as the PRR or ATSF with
thousands of cars coming through hundreds of interchanges every
day. Consider the fact that all of the paper with that
information flowed into the system car accountant's office with
time lags of days to weeks. Then imagine the massive clerical
task to do the count. No computers around to help. Not even
photocopiers !

It would have been a huge expense to get information that would
have been too old to use for any kind of management decision making.

But wouldn't that information be needed every day to pay for per diem
charges?

Jack Burgess
www.yosemitevalleyrr.com