Question on setting track height

[mjolnir]

My post wasn't about how to lay track; it was about how to interpret what is shown on the N&W track chart.

ns

 

[Jayco-man]

cascaderailroad- I don't have a video camera on my setup. Wish I did.

 

[cascaderailroad]

With free Skype all you need is a microphone on sitting on your desk, to talk loudly into ... "Share Screens" is an easy video/voice call, so you could see my screen, and I could see your screen ... no need for a webcam, and other stuff

 

[Jayco-man]

Ok guys I need to get going on this, I just need someone to tell me how to transfer the track data that I have into Trane data, and which one to use it in, either vertex height or gradient "k". What is the K for? The track data I have is like this -0.045. There has to be a way to transfer that data to Trane. It has to be simple if your an engineer and I'm not. I also printed out a list of trees for that area and all I can find in game is two types, that's sad. I also need a four land road with concreate median in the center. Cant find in game or on DL. Thanks in advance.

 

[mjolnir]

Vertex height and gradient percent are related, and you can use either. If you know the heights at two points on the right of way and set the height of those two points in Trainz, assuming the track distance between the two points is about the same, you'll automatically create the grade. If you know the height of one point, the accurate location along the right of way, and the grade, you can set the track, and use the "apply gradient" tool to set the height of the next point. Note that the sign of the grade refers to direction of the grade. If you're at point A, and the grade to the next point, B, is negative, you're going down hill. If you're at point B, and going to A, the value of the grade will be the same, so that if A to B is -0.45, the grade from B to A will be +.045.

The grade is calculated by finding the difference between two track heights, dividing that difference by the distance along the track between the two, and multiplying by 100, because grades are expressed in percentages. If the height at point A is 695 feet, the height at point B is 645 feet, and the distance between A and B is 4000 feet, then subract B from A (in this case, the reminder is 50 feet), divide by the track distance (in this case, 4000 feet). The quotient of 50 / 4000 is .0125. Multiplying by 100 to make a percentage means that the grade is 1.25 percent. To work backwards, if you know you have a grade of 0.045 divide by 100 to get .00045; multiply this by the distance along the track in feet (if we use the 4000 already described, the product is 1.8, which means that the difference in height between two ends is 1.8 feet. 1.8 feet in 4000 is essentially flat.

As a practical matter, if the percent grade is greater than +4 percent, or less than -4 percent, check your math, because it's possible you've made an error. The long time steepest grade on a US mainline railroad was on the NS at Saluda, with a grade of 4.7 percent. The current steepest grade in the US is on the City of Madison (IN) Port Authority railroad, which has a rise of 413 feet over a distance of 7012 feet, for a grade of 5.89 percent.

You might want to view this Youtube tutorial.

ns

 

[cascaderailroad]

You lay all your track from looking straight down from above ... then slightly sink the track so that only a few spline points barely show ... then you fine tune them by measuring a spline point height ... and if it is slightly sunken ... then type in a numeral that is 0.10m higher ... and keep repeating adding 0.10m numerals until the spline point is just above the terrain

If one gradient is 5.00 % and the next is 1.00% ... average it out and make the two gradients equal at 2.50%

There is no magic track spline point height measurement tool, nor is there a mathematical calculator ... it is all done by guestimation, and trial and error ... The DEM should be pretty close to the real spline point heights

 

[Jayco-man]

Ok thanks guys. Ok I started @ my one end and started to put in the gradient 0.045 not using the - . I used the video you gave on you-tub and used that method to set the direction of my grade. I did enough to drive on and in drive mode I see the gradient showing 0.04% and when driving one way shows 0.04% and the other way back shows -0.04%. Can you confirm that the 0.04% is a good conversion # from my 0.045? I don't have true #s for the first 5.5 miles west of Williamson so I'm just going to use the first gradient that starts on my chart file, or should I try to get good #s before I proceed. Can they be changed later if I can acquire the good #s? I checked both east and west and both are showing the same. I haven't used the smooth tool yet. I will waite and use it later when I have more done. Thanks again for the help.

 

[cascaderailroad]

It is a great idea not to use the "Smooth Spline" tool, till many months down the road ... and to lay track looking straight down from directly above

I get pretty good results by using my method of guestimation, of gradients, by typing in numerals

0.04 is just slightly less steeper than 0.045 (as the difference is only 0.005) ... usually just typing in to the hundredth place is accurate

I can teach you the basics by using Free Skype share screens, that way I can see your monitor, and what difficulties you are having

I lay all the straight stretch s, and straighten those tracks ... and connect them with curved tracks

What area does your DEM cover ? From what town, to what town ... and I will try to dig up some trackcharts that show gradients

 

[mjolnir]

Jayco-man, the only two instances you should ignore the "-" in a grade, is if the grade is measured in the opposite direction of travel, that is, you're laying from left to right, and the grade is measured from right to left, or if the amount of the grade is given as "-0.00". Otherwise, if the grade is shown with a "-" in the direction you're laying track, and you omit it, you're putting in a grade in the wrong direction, and laying a rising grade instead of a falling one.

ns

 

[ctclark1]

It is a great idea not to use the "Smooth Spline" tool, till many months down the road ... and to lay track looking straight down from directly above

Only problem is that if you are trying to lay an accurate grade from a track chart, you need to be mindful of the fact that straightening the track later changes the length of the spline that was straightened, which affects your final grade, which means your original grade was probably wrong. Not saying you might not have a different method, but when I'm laying an accurate (proto) track, I'll work with the straights/curves first to get them as close as I can (including straightening what needs to be straightened) then go back and do grades, because as I said the length (and therefore the calculation Trainz uses to apply the gradient number that you and I both enter) is different, which means the second spline points are at different heights.

 

[cascaderailroad]

I should have said "NEVER" use the "Smooth Spline" tool button until your base, and the summit, of the grade spline points are absolutely, positively, in agreement with Google Earth heights, and in agreement with trackcharts, as well as in agreement with topo map benchmark readings ... once you blindly assume that they are correct, and later on find out that they were in error, way off ... when you hurry to use "Smooth Spline" you deform the entire grade ... as if the first spline points are off by 10m, all the rest of the spline points gradually begin to build compound errors, off by 20m, 40m, 60m, 100m ... etc ... and by the time you get to the top of the grade you have messed up the entire grade(s), making an unrealistic mess of the DEM, which is irreparable ... I lost 3 years of work, and had to start over again as my DEM gradients were way off ... I often drive, gliding through dirt mounds, for well over a year, until I get the gradient(s) absolutely perfect ... after they are perfect, then and only then, do I use the "Smooth Spline" tool button.

Using the "Smooth Spline" tool prematurely is like rushing to spray paint an automobile ... and when it dries, it is a horrible mess of pits and scratch's

 

[mjolnir]

... if you are trying to lay an accurate grade from a track chart, you need to be mindful of the fact that straightening the track later changes the length of the spline that was straightened ...

In a track chart, the distances shown in the chart are by track mile, not "straight line", or "crow fly" miles.

ns

 

[mjolnir]

the grade spline points are absolutely, positively, in agreement with Google Earth heights, and in agreement with trackcharts, as well as in agreement with topo map benchmark readings

I would note that, depending upon the materials being used, these items, that is, the heights in Google Earth, the heights shown in the track charts, and topo map benchmark readings may not agree. It may be necessary to determine how these items can be reconciled to account for differences in the measuring tools, or errors which might have been discovered after one item was done, but before other elements were complete.

ns

 

[cascaderailroad]

https://www.youtube.com/watch?v=MQ5nZ5DlKl8

I am guessing that this route will be a real challenge, with hundreds of curves and many tunnels, with eastbound trackage @ 1.00% in some places

 

[cascaderailroad]

We just had a conversation on Skype, and we found out that trackcharts are a thing of the past ... as Google Earth has an option to show the exact height, in the metric system, where ever the mouse pointer is moved to.

So you can draw a ruler/metric/line on any given straight away track, and use those 2 heights, by typing them into the "use height" tool box, and apply them into the 2 spline points in Trainz, on that straight section of track ... setting the gradients by trackcharts is a thing of the past !

 

[Jayco-man]

Thanks I have that cd, just got it a couple weeks ago. Already watched it twice already. Just finished laying about eight miles tonight, just have a couple other things to work out and I'm going to try your theory out and see how good it works. Have from Nolan W.V to just West of Williamson yard about where the bridge cross the Pond River.