Track Elevation query

[JADsHome]

When laying track you can set the elevation on each modular section with the elevation on the elev: bar of the object info window of RE. This value can be increased to suit or by default increase/decrease by +-0.150 per select.

Does anyone know what this figure denotes please ? For example is it 0.150 of a meter rise per 100 or something else and is this constant ? Meaning if I were to lay a 25m section at +0.150 would that rise the same amount over 100m as 4x25m sections ?

Reason for asking is I need to contruct a bridge for a route in progress using GMAX that has an incline at one end starting at 1.050 and decreasing over the distance of 530m odd to level. I need to know how much to raise the point on the line on the model for each section of track (consisting of 6x50m starting at 1.050 decreasing in 0.150 intervals per module, 2x100m from 0.150 to level, an 18m level module and 2x250m 10deg level sections).

Hope someone can help - and I've put the above in understandable English

[tonyhap]

I cannot give you a mathematical answer. But I can tell you how I would make a bridge for the different inclines of some track already laid. I call it the “Trial and Error” method!!

I would make a separate bridge for each section of track having the same incline. Then link them together as one object.

To get the height difference, delete the track at each end of the track that has the same incline. Install a short piece of track at each end and leave it level. Note the elevation of each piece. Subtract the two. You have the height difference. Exit RE without saving!

Use this height difference in meters to construct your first bridge section. Export it to MSTS. See if you need to make any minor changes – left, right, up or down etc. And so on. Leave all texturing to the very end.

If your bridge has many arches, I would make a simple twelve faced box to get the correct incline. Then I would make the final shape, aligning vertices in Gmax with the simple box in Gmax. Then I would delete (or not link) the simple box.

Good luck!

Regards,
Chris

[Cobos]

In real terms 0.15 is approx a 1 in 381 gradient.

Yes, if you lay 4x25m pieces at a rise of 0.15 each, this will be the same as laying 1x100m piece at the same angle.

For Gmax, whatever angle you incline your track at, is the rotation value you apply to your shape in Gmax.

[bigvern]

It's an angle or inverse tangent. For some reason MS and Kuju chose this peculiar and obscure method of defining gradients rather than the more user friendly 1 in xx or % method of expressing the value. I guess at the time, they thought only those who qualified from M.I.T. would actually be building routes.

Can't remember the calculation now to get the correct figure though there are a couple of conversion charts kicking around on the net. It's been over two years since I built anything in MSTS however you can get finer results using the mouse and (I think) the Ctrl button.

As regards different gradients on the same bridge, I would say forget it. It's hard work aligning structures to the track bed with a constant gradient, let alone one which changes. Compromise.

Edit:
To calculate the "angle" divide the fraction i.e. 1 div by 381 then multiply the result by the inverse tangent which will give, as Cobos says, the angle of 0.15. In the RE you will have to rotate this down to -0.15 for a falling gradient.

Good old Kuju!

[fadedGlory]

Can't remember the calculation now to get the correct figure though there are a couple of conversion charts kicking around on the net. It's been over two years since I built anything in MSTS however you can get finer results using the mouse and (I think) the Ctrl button.

Hold down the END key, keep the left mouse button down, and moving the mouse towards or away from you will change the gradient in small steps.

fG

[leveritt]

When laying track you can set the elevation on each modular section with the elevation on the elev: bar of the object info window of RE. This value can be increased to suit or by default increase/decrease by +-0.150 per select.

Hope someone can help - and I've put the above in understandable English

Here's a link to some grade and curvature calculators that I put up some time ago.
http://forums.flightsim.com/ts/dcboard. ... 8244#88254

Entering 0.15 degrees into the Gradient Converter yields "1 in 381.97" and "0.26%".

regards,
charlie

[96smitro]

An alternative to aligning the said bridge is to create a custom object, built at the right angle to the track (I used the conversion tables to work out the xx in 100 gradient, and then created guide lines along the angle). I have done this for parts of the route I am constructing (not bridges though, tunnel wall sections).

Rob.

[JADsHome]

Excellent - thankyou all for your input.

Tonyhap - To get the height difference, delete the track at each end of the track that has the same incline. Install a short piece of track at each end and leave it level. Note the elevation of each piece. Subtract the two. You have the height difference. Exit RE without saving!

Think I will try this method to start.

Leveritt - thanks for the calculators - have downloaded these and will see how I get on.

BigVern - To calculate the "angle" divide the fraction i.e. 1 div by 381 then multiply the result by the inverse tangent which will give, as Cobos says, the angle of 0.15. In the RE you will have to rotate this down to -0.15 for a falling gradient.

Leveritt's calculators will hopefully give me this but thanks this will come in useful.

[longbow]

The transitions you propose will give you quite visible kinks in the track and more particularly in the bridge and life will get very complicated if your bridge arches don't match the track lengths, so you might want to consider whether it's not better to avoid them. I would imagine on the prototype that most bridges are built to a constant gradient anyway for structural reasons.

As for aligning the bridge, the best way to do this is precisely is by setting the centre (origin) of the bridge shape to coincide with the centre of the first track piece; you can then use copy and paste the track piece's world file co-ordinates and orientation over those for the bridge shape. I align all my platforms and bridges this way.

[steam4me]

Does anyone know what this figure denotes please ? For example is it 0.150 of a meter rise per 100 or something else and is this constant ?

http://steam4me.railpage.org.au/trainsi ... .html#grad may help.

There are lots of other tutorials on Route-Building at the same place.

Regards

Yuri, webmaster
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[tonyhap]

I have to agree that you could run into problems with the arches if you use separate bridge pieces for each different incline. So why not make a one piece bridge top?

I would unlink all the separate pieces made earlier, but keep them in Gmax as profile templates. I would make one new box with the appropriate segments that would go all the way from one end of the bridge to the other. I would align the top part of this new box with the profile templates so that it matches the track bed. I would align the sides of the new box to the track, all curves, if any, and straights. I would make the bottom face of this new box equal to the height of the bottom of the semi circular arches – their centres. So then it is simple arithmetic to work out how many arches I want, where to put them, and their size. I make my arches by placing horizontal cylinders and then use the Boolean substraction to make the actual arch.

I would then make two pillars to support the bridge. One pillar would be for each end and one would be for all the middle locations. Remove all unseen faces, and the basic shape is done.

Regards,
Chris

[JADsHome]

Relaid all the track to be one gradient (1:76 or 0.750) all the way along the length (almost 800m long with a curve at the end). Constructed the model in GMAX using TonyHap's height difference method in the end. Now have my completed [bespoke] 30 arch stone bridge in my route.

Thanks again for all your help. Incidentally found this page by Peter Holton of great help... http://www.3dtspeter.co.uk/viaduct_tutor/