Gradients and Track Height

alco_power

New member
Hi, just a quick question

is there a tool apart from DEM' tools that can approximatly calculate gradients in surveyor mode? or a way to tell how "track height" or Spline height can be compared?
if that makes any sense
for exampe 1 in 20 grade what would that equal in "spline height" over a distance


Thanks

ps: or even HOW are grades calculated?
 
Hi, just a quick question

is there a tool apart from DEM' tools that can approximatly calculate gradients in surveyor mode? or a way to tell how "track height" or Spline height can be compared?
if that makes any sense
for exampe 1 in 20 grade what would that equal in "spline height" over a distance


Thanks

ps: or even HOW are grades calculated?

Howdy............ To the best of my knowledge, the grade is a percentage in DEGREES from one point to another. To use your example of "1 in 20 grade". Over a given length of "20", the track would either raise or lower a number of "1". Simply stated, if a track is 20 meters long, and starts at one end at "0 meters", it will be "1 meter" higher or lower at the other end. To obtain the actual percentage grade, you divide the 1 by 20. In this example it equates to a 5% ( 5 percent ).

I treat "spline height" and "track height" as one and the same if we are talking tracks or bridges. There might be a difference. I am sure someone will comment and clarify. Now if you were to select a gradient of 5 degrees, and then lay track from one point to another, then you can use the "get spline height tool" which will tell you what the height is at either point. Obviously that height will vary between the two points, either increasing or decreasing along the track between those two points. You can now elect to use the "set spline point" tool to keep a certain track height. If this makes no sense, I am sure other members will clarify, but I hope it helps.:wave:
 
Good explanation, but I wanted to clarify one thing. The slope is not a percentage in degrees. It's just a percentage. For example, (this is not a railroad example), if a line rises 20 units over a horizontal distance of 20 units, then the slope is 20 divided by 20 which is 100%. This also happens to be a 45 degree angle.
 
Good explanation, but I wanted to clarify one thing. The slope is not a percentage in degrees. It's just a percentage. For example, (this is not a railroad example), if a line rises 20 units over a horizontal distance of 20 units, then the slope is 20 divided by 20 which is 100%. This also happens to be a 45 degree angle.

Thank you Leeferr for the clarification. I had the percentage/degree stuff all mixed up. Anyone know what the maximum gradient known happens to be??? I heard some South American mountains have some short but very steep ones, but I have never bothered to investigate.:confused:

I just found a thread under Prototype Talk. It is titled "Steepest Mainline Rail Grades". I think it is all United States though.
 
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If you include cable and cog railways, it can get pretty steep, but not sure what the steepest is. Some trainzer out there will know though. I once rode the inclined railway in Hong Kong, but that was about 30 years ago and don't remember much about it. I believe that it was a cog railway. Does anyone out there know?
The inclined railway in Chattanooga, TN is a cable line that is steep, but again, I don't know the grade on it either. There is one section of the line that is fairly steep though. I've ridden it many times.
 
The south cliff railway in Scarborough, England, has a gradient of 1:1.75 :)

The central cliff & the north cliff are 1:2

St Nicholas Cliff is 1:1.33

sc22.jpg
sc19.jpg


sc15.jpg

sc3.jpg

north09.jpg
 
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I just looked up the website for the inclined railway in chattanooga and it states a grade of 72.7% at its steepest point.
 
Grade

I was just reading Railroad Engineering by William Raymond, John Wiley & Sons, 1909. He states that " A little over 4% is the heaviest grade in regular use on any important road, but heavier grades, approximating 6% exist and are operated on some mountain, mine and logging roads." "The steepest trolly grades are about 15%."

He goes on to say that a locomoting with only driving wheels and no tender in theory, could just maintain itself at a uniform slow speed on a grade of about 24.75%. Has anyone tried that in TRAINZ?

DAP
 
....Anyone know what the maximum gradient known happens to be??? ...

In the UK, the steepest mainline railway is the Lickey Incline, south of Birmingham. This has a gradient of 1 in 37 (2.7%). The steepest gradient adhesion-worked (ie. without rack, cog or cables) was the Hopton Incline at 1 in 14 (7.14%) on the Cromford & High Peak Railway in the Pennines, which also had several cable-worked stretches, unfortunately closed in the 1960s. (I'm unsure if there is anything left between those 2 on any remaining branchlines or industrial lines in the UK) The steepest narrow-gauge line is 1 in 12 on the Snaefell Mountain Railway on the Isle of Man. Although this has a centre rail, this is only used for braking on the way down, the up journey is entirely adhesion worked.
 
A good rule of thumb to remember if building in the USA is to keep your track around a 4% grade. 6% is steep and 3% is better. It's what I was told many years ago when I was building 'mountainest' track in HOn3. This will keep it within a more realistic world, so to speak.

As mentioned above, there are steeper grades around.

Rick:)
 
The Mainschleifenbahn has a 1:23 grade, its the steepest in Bavaria I think. In 10KM it lowers 100M, really would have been neat to see in the 70's when oil trains were running all over the thing.

WileeCoyote:D
 
A good rule of thumb to remember if building in the USA is to keep your track around a 4% grade. 6% is steep and 3% is better. It's what I was told many years ago when I was building 'mountainest' track in HOn3. This will keep it within a more realistic world, so to speak.

As mentioned above, there are steeper grades around.

Rick:)
4% as a rule of thumb? Well. That's the maximum value allowed in Germany for branch lines, ramps of dedicated commuter lines and high-speed passenger only lines. Otherwise it's much lower: Just 1.25%. Some of the trans-Alpine routes are steeper. The Gotthard is 2.2%, and that's too steep for efficient operations.

I'm aware there are steep US mountain routes. But 4% for a mainline? Raton is one of the steeper ones. 3.5% as far as I know. When did Santa Fe build the bypass? Decades ago.
 
Howdy............ To the best of my knowledge, the grade is a percentage in DEGREES from one point to another. To use your example of "1 in 20 grade". Over a given length of "20", the track would either raise or lower a number of "1". Simply stated, if a track is 20 meters long, and starts at one end at "0 meters", it will be "1 meter" higher or lower at the other end. To obtain the actual percentage grade, you divide the 1 by 20. In this example it equates to a 5% ( 5 percent ).

I treat "spline height" and "track height" as one and the same if we are talking tracks or bridges. There might be a difference. I am sure someone will comment and clarify. Now if you were to select a gradient of 5 degrees, and then lay track from one point to another, then you can use the "get spline height tool" which will tell you what the height is at either point. Obviously that height will vary between the two points, either increasing or decreasing along the track between those two points. You can now elect to use the "set spline point" tool to keep a certain track height. If this makes no sense, I am sure other members will clarify, but I hope it helps.:wave:


Hey there thanks so much to all for your replies and the great pictures of the beach railway gradient thing haha um, i kinda get it now i just wasnt sure thats all ! but thanks for taking the time to help me

Thanks!
 
Hi, just a quick question

is there a tool apart from DEM' tools that can approximatly calculate gradients in surveyor mode? or a way to tell how "track height" or Spline height can be compared?
if that makes any sense
for exampe 1 in 20 grade what would that equal in "spline height" over a distance


Thanks

ps: or even HOW are grades calculated?

I've found a great tool for working out gradients. Try this http://www.railpage.org.au/trainman/grade.htm

regards

Harry
 
@ goephil,
That's why I used the word, 'mountainest' in humour. I was assuming he was referring to a mountain route or wanting to climb or descend a mountain and wanted to know what would be realistic. Naturally 0% would be perfect but, I never met a flat mountain. :D

Rick
:)
 
I was assuming he was referring to a mountain route or wanting to climb or descend a mountain and wanted to know what would be realistic.
So was Geophil. Even thru the montains you won't see much over 2% grade on any main line for std gauge in the US. There are exceptions that we all like to point out but they are just the exceptions.

Even NG didn't always climb vertically. The EBT rr a 3'ng coal hauler in the Appalachians of Pennsylvania limited the grade south bound with the empties to 2.8% and north bound with the loaded hoppers to 1.5%. They hauled the same no of cars in each direction. 4% on branch lines is pretty steep - the EBT severly restricted the tonnage of the locos on it's 4% branch. 6% is more typical for logging rr and geared locos.

Few people really seem to appreciate the effect of grade on train transportion. A 2000 ton freight train traveling at 50 mph on the level requires about twice as much force to haul it at 50 mph up a 0.2% grade. And that's a far cry from a 2% grade that might require helpers to negotiate at a reasonable speed.

Bob Pearson
 
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