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Thread: Should gradients exaggerate on realistic terrain?

  1. #1

    Default Should gradients exaggerate on realistic terrain?

    Hi, I have been laying tracks on DEMEX-generated routes. I follow gradients provided from track charts while laying tracks. Sometimes, if I lay tracks downhill, the track will be higher from the ground than the actual height. I suspect it also happens when I lay track uphill. The track will be lower or submerged unlike the actual track. I'm unsure if this is a known issue in the game. Has anyone made their track gradients regularly steeper than the figures provided from the track charts they reference from? Thank you.

  2. #2
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    You mean the terrain doesn't exactly match the track gradients shown in the charts? That's why cuts and fills exist in the real World. You can either form the terrain to the track (using either the Y key or F key depending on the software, or use embankment shapes for fills, which I think looks better

  3. #3

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    Quote Originally Posted by ebnertra000 View Post
    You mean the terrain doesn't exactly match the track gradients shown in the charts? That's why cuts and fills exist in the real World. You can either form the terrain to the track (using either the Y key or F key depending on the software, or use embankment shapes for fills, which I think looks better
    The cut or fill may not exist at the spot where the track is too high or low relative to the terrain. Or if above the ground, the height of the fill isn't close to the real fill's height at the spot, according to the elevation provided by Google Earth.

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    What is the terrain's resolution? It has to be pretty high (<20m) for terrain work to show up in DEM data. I have 30m resolution and can see some of the larger cuts and fills in my projects, but you have to know what to look for for most. How far off the terrain is your track? Depending on the railroad, large earthworks may be a common thing. GN, for one hated hills and valleys and would do anything in their power to avoid going over or into them

  5. #5
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    I use 1/3 arc-sec terrain data. I have found that the DEMEX generated terrain is usually slightly
    lower than I would expect. I first noticed this when I was doing the RMD-3 for Lukas, who was
    going to use my track, along with the RMD-4 to create the RMD-West. I also noticed it doing the
    MCOA2 route. Generally, the track, on fills, was about 2 meters high, and in some cases where
    there should have been a shallow cut, this difference "filled the cut". However, most of us will
    not be on this planet long enough to get it exactly right, so if the difference is great, say more
    than maybe 3 meters, then one possibility would be to regenerate the terrain in DEMEX, using
    the height offset option. Personally, I don't see it as a problem, 90% of the time. Lay the track
    as accurately as you can, using the track charts. Some track charts also show the elevation
    above sea level and that certainly helps. Also, elevations selected off of Google EArth may vary
    considerably from the real world and judgment is needed there. Remember, T-S relies mostly
    on visual effect. It ought to look good from the locomotive cab, or the dome car, but is likely
    not to be perfect, not even close.

  6. #6

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    Having track charts and 1/3 arc seconds are already luxurys not available in most parts of the world. I have had to work all routes in areas i am interested in with 1 sec SRTM DEMs (30m resolution) & no track charts. Everything is "eyeballed" off Google Earth (even this has its limits), photos where available, and some common sense.

    I have to agree with the comment above, if it looks reasonable its probably good enough in my book! Also scenery objects in the end can easily make up for the realism. No point having inch perfect terrain if the scenery later on does not match.

    One rule I do try to obey is the ruling gradient, as far as possible i avoid exceeding what is specified for the route.
    Last edited by joe_star; 07-18-2020 at 09:24 AM.

  7. #7
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    As far as I know, track charts are only available in the U.S. I was able to collect what I needed
    while I worked for CSX and later contractors. Now, at www.railfandepot.com you can find a large
    number of track charts including some I would not have expected. These cost a nominal fee to
    download (.pdf files). As a member of the Louisville & Nashville historical society I have obtained
    some from the "store" for a small fee. Somewhat more costly for non-members but not exorbitant.
    I also got material for one route from the Great Northern society.

    J. H. Sullivan

  8. #8

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    Quote Originally Posted by ebnertra000 View Post
    What is the terrain's resolution? It has to be pretty high (<20m) for terrain work to show up in DEM data. I have 30m resolution and can see some of the larger cuts and fills in my projects, but you have to know what to look for for most. How far off the terrain is your track? Depending on the railroad, large earthworks may be a common thing. GN, for one hated hills and valleys and would do anything in their power to avoid going over or into them
    I don't remember the terrain's resolution in meters, but it is 1/3 arc second resolution. My particular issue is that I'm trying to have the track enter a cut on a downward grade. It keeps staying higher from the ground despite of my effort to increase the downward gradients before the cut.

  9. #9
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    If you consider that to be a serious issue, I would regenerate the routes terrain and raise it by 1-2 meters using the height
    offset too. To raise 2 meters, key in 2 in the box. If that turns out to be too much, try 1 meter etc. This is why, I don't
    usually sculpt a lot of terrain until all track is in place, because what may be too high or low at one point, may be just the
    opposite somewhere else. "Guesstimation" may be required. I should also point out that when you generate DM terrain,
    it is good to lower that by 20-50 meters to avoid gaps in the terrain that will show us as slivers of white. Even then it is
    often necessary to use vision blockers like dense groves of trees to at least conduse the view.

    J. H. Sullivan

  10. #10

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    Since it was difficult to make the cut at that spot, I decided to update the gradients of 40 miles or so of track and discovered that I laid one 0.50 or 0.60 mile segment uphill rather than downhill per track chart. After additional tweaks, I finally had the track around the same level as the cut and I'm satisfied with the result in the meantime. Thank you for the help.

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