Question about (US) grade notation

J

Jananton

Yesterdayz Trainz member
Hi All,

Obviously gradients in trainz are expressed in procents, however I came across a real life grade table that looks like this example:
milepost 8.1, west grade 44, east grade 23, and so on.
How must I understand numbers like 44 and 23 ? Is this feet rise/descent per mile (normal or nautical?) or something else maybe.

Thanks in advance.:)

Greetings from nighttime Amsterdam,

Jan
 
Most US topo maps elevations are displayed in 20 foot increments. Track tick marks are spaced evey 1/10 of a mile.
Trainz however uses the metric system.
Canadian topos are in metric, and elevations are displayed in 50 meter increments.
A 2.5% gradient is really steep for a mainline. The PRR tried to have a maximum limit of 1.25% gradient.
English/Metric equivilents: http://forums.auran.com/trainz/showthread.php?p=477661&highlight=metric#post477661
 
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The figures 44 and 23 are likely the rise or descent of elevation per mile of track from the milepost in their respective directions. There are several ways of specifying a grade (see the wikipedia article here).

In Trainz the grade (or Gradient, as it is apparently termed in the advanced track tab in surveyor) is represented as a percent (again, the wikipedia article has a nice diagram showing the equivalent values for a percent grade to the actual degress in rotation from the ground the slope is (i.e. 100% grade is 45 degrees, 50% equals 26.57 degrees, etc.). You can use the minimap (from the top menu bar in surveyor or bottom-right in driver mode) to view the average grade for any given section of track (make sure the 'View Gradients' option is ticked in the minimap view options).

To convert the values you have above into a grade, use the following forumla:

the rise (or drop) in elevation / 1 kilometer/mile (depending on what units you're using) x 100.

I'll provide an example, though since I don't know which country's railroad those values were taken from, I'll assume they are imperial units given the title of the thread (correct me if I'm wrong):

44 feet / 5280.01 feet (which is 1 mile, by the way, and people wonder why 99% of the world uses the metric system -sigh-) x 100 = a 0.83% grade for the western side of the milepost.

A final note, remember that only grades that go up are a positive number, A descending grade is negative.
 
Xengeance said:
The figures 44 and 23 are likely the rise or descent of elevation per mile of track from the milepost in their respective directions. There are several ways of specifying a grade (see the wikipedia article here).

[Known Surveyor grade options snipped]

To convert the values you have above into a grade, use the following forumla:

the rise (or drop) in elevation / 1 kilometer/mile (depending on what units you're using) x 100.

I'll provide an example, though since I don't know which country's railroad those values were taken from, I'll assume they are imperial units given the title of the thread (correct me if I'm wrong):

44 feet / 5280.01 feet (which is 1 mile, by the way, and people wonder why 99% of the world uses the metric system -sigh-) x 100 = a 0.83% grade for the western side of the milepost.

A final note, remember that only grades that go up are a positive number, A descending grade is negative.
Click to expand...

Thanks for the confirmation of my initial thought of feet per mile and the handy formula. Your assumption of imperial units was right the route I'm checking this for is in California USA and ran from Merced to El Portal. The coin will drop for railroad historians now.:hehe:

I initially wanted to try a DEM generated map, something I haven't done before so I picked one from filipsatwork that took my fancy.
I should have checked of course, but since then I've found out that others are having a try at this one as well. Because of that, as well as it beiing a first attempt one must see this more as an exercise then an inch by inch representation of the real thing.

Knowing now what the numbers in the milepost tabel represent creates a big puzzle, since the DEM map shows a plateau that's 40 meters higher then can be reached with the provided grades. Even with the knowledge that a DEM map can be off 20 meters in all directions I'm still stuck with a gap of 20m. :)

Maybe it's time to see if I can find some (free) topographical maps of this part of the world as cascaderailroad mentioned in the other thread he mentioned here. (Thanks for that, interesting read)

Greetings from sunny Amsterdam,

Jan
 
G'day Jananton,

gfisher wrote...

..."...According to my engineering handbook a mile is 5280.0 feet......where does the 5280.01 come from?..."...

...which caused me some wonder, as well!!

However, it is, indeed, quite possible that the 'values' 44 and 23 are intended to be "percentage gradient values" but since Xengeance has clearly indicated his U. S. origins, he has completely failed to take into account that these might be European (read "the rest of the world") values, in which case they would be expressed as a ratio '1 in 44' and '1 in 23' respectively, which refer to the ascent or descent of the gradient as the ratio of the rise along the length of the gradient. Allow me to explain...

...if the ratio is expressed as '1 in 44', for example, this means that the grade rises (or descends) 1 unit in height for every 44 units the track goes along horizontally. Using this method completely removes the relience on any form of specific measurement system, since the gradient angle remains the same, no matter what unit of distance measurement is used...

Jerker {:)}
 
As a DEM is quite nice, as it builds all the terrain, they are a bit hard to lay gradients on. As rivers and trackmarkings can be off +/-20' in all the x-y-z axis.

Don't overlook "Basemaps" as any Topo Map or Google Earth image can be "pasted" right on you Trainz baseboards. Laying your own gradients and making all your own terrain can be fun and easy also. A developed learning curve skill and technique.
 
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Hi Jan,

If you are modeling the YVRR, you might ping Jack Burgess (http://www.yosemitevalleyrr.com/) - his email is at the bottom of the page. He also has a Yahoo group at http://finance.groups.yahoo.com/group/YosemiteValleyRR/ which is good for questions like that. There should be someone there that could answer questions related to meaning of specific signage for that railroad.

For free US topo maps, try MSR Maps (formerly Terraserver) at http://msrmaps.com/Default.aspx

Greetings from rainy Portland,
Curtis
 
Hi All,

Jerker said:
G'day Jananton,

However, it is, indeed, quite possible that the 'values' 44 and 23 are intended to be "percentage gradient values" but since Xengeance has clearly indicated his U. S. origins, he has completely failed to take into account that these might be European (read "the rest of the world") values, in which case they would be expressed as a ratio '1 in 44' and '1 in 23' respectively, which refer to the ascent or descent of the gradient as the ratio of the rise along the length of the gradient. Allow me to explain...

...if the ratio is expressed as '1 in 44', for example, this means that the grade rises (or descends) 1 unit in height for every 44 units the track goes along horizontally. Using this method completely removes the relience on any form of specific measurement system, since the gradient angle remains the same, no matter what unit of distance measurement is used...

Jerker {:)}
Click to expand...

Well, at first glance the ratio approach could make a difference. But when running some numbers through the pocket calculator, allthough 1/44*100=2.27% looks promising, 1/23*100=4.35% imho is out of the question for a railroad where the loaded trains, lumber and ore, go prodominantly downhill. I think that soon would become a nightmare.:hehe: Also a provided contour map shows the 23 part much less steep then the 44 part.

If you want to have a look at the grade tabel you can find it here. (click on the link 'Railroad details')

cascaderailroad said:
Don't overlook "Basemaps" as any Topo Map or Google Earth image can be "pasted" right on you Trainz baseboards. Laying your own gradients and making all your own terrain can be fun and easy also. A developed learning curve skill and technique
Click to expand...

I have used basemaps (with google earth pics) to plot out a large industrial iron and steel complex over here in holland, just to see how that would work. However the dutch countryside is very, very flat in contrast to the terrain between Merced and El Portal. I don't think basemaps, or better the picture in it, follows the contours of the terrain over the hills and/or mountains when laid out over it.
Maybe if you make them semi transparent...

Pencil42 said:
If you are modeling the YVRR, you might ping Jack Burgess (http://www.yosemitevalleyrr.com/) - his email is at the bottom of the page. He also has a Yahoo group at http://finance.groups.yahoo.com/group/YosemiteValleyRR/ which is good for questions like that. There should be someone there that could answer questions related to meaning of specific signage for that railroad.

For free US topo maps, try MSR Maps (formerly Terraserver) at http://msrmaps.com/Default.aspx
Click to expand...

I knew the names of Merced and El Portal would be a giveaway :hehe: , so yes, that was the DEM map that took my fancy. To say modelling is maybe a little much though, I would be glad if I'm able to catch the atmosphere of such a kind of railroad round the 1910-1930's. The site you mention is in fact the one I found most of the info about the Yosemite Valley Rairoad, including the puzzling grade tables. That btw are fully called west rule grade and east rule grade. Maybe that additional word "rule" does fire a lightbulb with somebody.;)

On topo maps I found this one. Has in fact the same problem as google maps in that stitching parts together precisely is a little hit and miss. I haven't tried your link yet, so I hope that will work better in that respect.

Greetings from nighttime Amsterdam,

Jan
 
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Hi Jan,

I think the site I posted is slightly different than the one with the grade tables. I did take a look at the grade tables, and it's an interesting conundrum. If it were actual grade information, you would thing the information would be symmetrical, but there are too many zeros going one direction with non-zero values going the other direction. I posted your question on the above Yahoo group, if they come back with anything, I'll pass it on.

Greetings from rainy, nighttime Portland,
Curtis
 
-My 2 cents is:
-Like how cascaderailroad was saying about base maps, u could try transdem. u can put google earth images on 1000x1000m utm tiles which will provide a better resolution image for u. u can check out more info at his site here:
http://www.rolandziegler.de/

-Joe
 
Hello Curtis,

Pencil42 said:
Hi Jan,

I think the site I posted is slightly different than the one with the grade tables. I did take a look at the grade tables, and it's an interesting conundrum. If it were actual grade information, you would thing the information would be symmetrical, but there are too many zeros going one direction with non-zero values going the other direction. I posted your question on the above Yahoo group, if they come back with anything, I'll pass it on.

Greetings from rainy, nighttime Portland,
Curtis
Click to expand...

I found that the look of that site depends on which link you click. It's either a white background with menu on the right, or a black background with a master menu dropdown list at the right bottom. :hehe: Ah, I now noticed you took the entrypoint to the model railway layout about the same route. All the same site if you ask me.

The asymmetrical numbering in the grade tables is exactly what made me wonder in the first place. The reason I posed the question here was my thought it might be a US surveying notation of some sort, unfamilliar to me. I should have given the link in my initial post, that would have been easier in retrospect.:)
Thanks you dropped the question in that yahoo group, I noticed I need to make a yahoo ID to see it and I'm not that keen to do that. I'm curious what the answers will be in respect to those tables.

socalwb909 said:
-Like how cascaderailroad was saying about base maps, u could try transdem. u can put google earth images on 1000x1000m utm tiles which will provide a better resolution image for u. u can check out more info at his site here:
http://www.rolandziegler.de/
Click to expand...

Hi Joe,

Well, I'm aware of transdem and its remarkable possebillities, and allthough very cheap for what it does, I first want to find out if map building this way is my cup of tea, so to say.:hehe:

Greetings from rainy Amsterdam,

Jan
 
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OK Jan,

Here's the answer from Jack via the Yahoo group:

Those tables are reproduced from the Employee TTs and show the ruling grade
in each direction in "feet per mile". To get the ruling grade as a
percentage, divide the number shown by 5280, the length of one mile, and
multiple by 100. So, "53" is 53/5280 times 100 or 1.00%. They are not
symmetrical since the track can have a slight "roller coaster" effect in
places with the track going up and down slightly due to the natural
topography. A "zero" would indicate that there is no ascending grade in that
direction. For example, westbound, the tracks follow the river between El
Portal and Detwiler and then need to climb to get up and around the
Exchequer dam. Likewise, the ATSF tracks are built on an elevated "levee"
and there is a slight climb (0.28%) both westbound and eastbound to this
crossing.

In reading this "table", the ruling grade is the number at the next station
in the direction you are going. Thus, the ruling grade between Snelling and
Merced Falls is 41' per mile.

It might seem that only the highest ruling grade over the entire line would
be important. While I've never seen photos nor read in the Dispatcher Sheets
of a freight double-header, double-heading (and even the occasional
triple-header) was not uncommon on passenger trains. In such cases, the
helper might be added somewhere up in the canyon or even assist only between
Incline or Moss Canyon and El Portal.

There is another table in the Employee TTs which goes along with the
information on the ruling grades and that is the Engine Tonnage Ratings.
Each group of engines (the 2-6-0s, the new 4-4-0s, and the No. 21) is listed
along with the maximum tonnage for the following sections of the railroad:
Merced to Merced Falls, Merced Falls to Bloss, Bloss to Moss Canyon, and
Moss Canyon to El Portal. The table also lists the number of empty log cars,
average number of loads, and number of passenger cars which can be pulled by
those engines over those sections of track. For example, the 22/23 can pull
9 Standard Pullman and ATSF coaches between Merced and Merced Falls but only
3 between Moss Canyon and El Portal. The 2-6-0s could pull 21 average loaded
cars between Merced Falls and Bloss. (These are all eastbound maximum
tonnages since the highest grades are eastbound.) But Dispatcher sheets
typically show more than 21 loaded log cars on Train 9 which means that that
train could run westbound but could not back up eastbound. This is confirmed
by the Sunrise to Sunset movie which shows the caboose being rolled down to
couple onto the log train.

You would think it would have been easier to list the ruling grade in
percent in the first place but many people were not that math oriented in
those days and didn't get exposed to percentages like we do today (49% or
the people surveyed like the idea, 79% of all TVs sold today are High
Def...etc.) nor were those with simple math skills comfortable with
decimals. But while Emory to Bloss had a 1.00% grade, Clearinghouse to
Incline had a 1.50% grade and Moss Canyon to El Portal had a 1.99% grade,
very significant in railroading but possibly beyond the math skills of
many...

Jack
Click to expand...
So, it looks like it's the steepest uphill grade from that point to the next point.

Hope that helps!
Curtis
 
Hi Curtis,

Interesting, so in fact it's indeed feet per mile, but only for the steepest part between two mileposts. The grade may vary, but not exceed the given number. Lets hope this will iron out most of my 20 to 40 meters height difference along the reservoir of the Exchequer dam.:hehe:

Thanks for taking the trouble posting Jack's response I've saved it immediately for later, probably much later reference, when testruns with representive consists come in play. :) .

Greetings from nighttime Amsterdam,

Jan
 
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