[darwins]

Not doing well at visualising your steam pipes this morning. Have you tried naming them as bogies (or as children of a virtual bogie)?

[Traindude]

darwins, on 25 February 2021 - 09:58 PM, said:

Not doing well at visualising your steam pipes this morning. Have you tried naming them as bogies (or as children of a virtual bogie)?

Keep in mind that I have not yet exported the model for use in the game yet.
I've added cylinders and the jointed pipes to help better illustrate the movement of the pipes (in red) relative to the cylinders (in green). Here is what it would look like on straight track:

And here's what it should look like when I slightly rotate the pivot point for the front chassis ("BOGIE1") to simulate the engine going around a curve:

So when the front chassis pivots, the front halves of the steam pipes "point toward" the cylinders (parented to the front chassis).

Does this clarify what I mean?

[ATSF3751]

Seems like now things are starting to heat up outside things are starting to freeze up on the forums! I do have some interesting news however when it comes to Milwaukee Road 261. Our group has decided to look into converting it over to oil fuel instead of running on coal. This would mean the locomotive could be used in coal and oil testing in Open Rails if we do decide to convert it over.

Brandon

https://www.trains.c...CWiNQxashBPkIwU

[Traindude]

ATSF3751, on 18 March 2021 - 01:27 PM, said:

Seems like now things are starting to heat up outside things are starting to freeze up on the forums! I do have some interesting news however when it comes to Milwaukee Road 261. Our group has decided to look into converting it over to oil fuel instead of running on coal. This would mean the locomotive could be used in coal and oil testing in Open Rails if we do decide to convert it over.

Brandon

https://www.trains.c...CWiNQxashBPkIwU

Yes! By comparing the results of different fuels with essentially the same locomotive, we can get more accurate results, even though I am sad to see one of the few Western coal-burning engines get the oil treatment. Maybe the Coalition for Sustainable Rail's torrefied biomass experiments might prove to be a successful stand in for coal.

In the meantime, I have an update on the experiments of making a single-unit articulated locomotive in Open Rails. I finally got the chance to export my experimental Challenger model (albeit sans-jointed steam pipes), and test it on the CTN Test Route's "Curve Branch" to examine the articulation effect. I have had some success with naming the front chassis "BOGIE1" and the rear chassis "MAIN", although I had to do some manual tweaking of the uncompressed .s file to get the front chassis' side rods to align with the wheels.


Here's a front-on shot of what the loco looks like on straight/tangent track:

This and all remaining screenshots were taken with the #2 camera zoomed all the way out and FOV set to 4 degrees.

Here's what it looks like rounding the CTN Curve Branch's 2000m curve.:

The loco doesn't seem to articulate like it's supposed to, nor does it articulate on the 1500m or 1000m curves.

On the 500m curve, the front chassis seems to jitter sideways slightly when the engine rounds the curve. However, on the 250m and 125m curves (the latter shown below), the loco does in fact articulate correctly:


If you'd like to see this for yourself, I have attached my test model to this post, which also includes the Blender source files I used for modeling (in case you wanted to experiment with them on your own), as well as a new path for the CTN Test Route.

[darwins]

Looking good. That incredibly long boiler makes me think of another aspect of steam physics. As tubes get longer and longer their capacity to evaporate water gets less and less. Most evaporation is around the firebox and firebox end of the tubes. Ideally locos would have a short fat boiler, but of course that does not fit into the loading gauge. Not sure if the designers there in US at some point said it seems like there is no value to making a boiler any longer than this.

[Traindude]

darwins, on 19 March 2021 - 11:56 PM, said:

Looking good. That incredibly long boiler makes me think of another aspect of steam physics. As tubes get longer and longer their capacity to evaporate water gets less and less. Most evaporation is around the firebox and firebox end of the tubes. Ideally locos would have a short fat boiler, but of course that does not fit into the loading gauge. Not sure if the designers there in US at some point said it seems like there is no value to making a boiler any longer than this.

I will admit, though, the boiler looks longer than it actually is because I modeled it smaller in diameter than on most 4-6-6-4 Challengers. Most Challenger boilers are 8-9 feet in diameter, but mine is only about 6-1/2 feet in diameter!

[NickonWheels]

Getting back to earlier themes, still why has ORTSBurnRate no effect on reducing the amount of coal in the tender?

[Traindude]

Sorry to bump this thread, but I did a little more experimentation with my Challenger test model. I have modified it to look a little less like "a tube on wheels". I have also began experimenting with the jointed steam pipes for the front cylinders. There are three of these pipes--one "intake" pipe on each side of the boiler and an "exhaust" pipe between and to the rear of the front cylinders. These jointed pipes are treated as "BOGIE" objects.



However, as you can see by the HUD, the wheel arrangement is correct.

I will admit though on tighter curves, particularly the 125 meter curve on the CTN test route, the front ends of the front steam pipes don't quite line up with the front cylinders, as shown below:



I have included the updated version for you guys to download below. It also includes my Blender source files, showing how everything works, such as using "Empties" for the Bogie pivot points.

Now all we need is a way to make the headlight emitter, as well as the cylinder cock steam emitters for the front cylinders and anything coupled to the engine's front coupler, "pivot" in sync with the front half of the chassis (which in my case is labeled "BOGIE1").