RailPro > RailPro Specific Help & Discussion

Revisiting our sound handling wish list

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G8B4Life:
Unfortunately Alan, that one would be hard to work out because of the complexities of train dynamics and our model dynamics. I'll give a couple of examples. This is probably going to be a bit boring for most but in the interest of prototypical operation...

I don't have load tables for US locomotives so the figures I'll present are made up but the principal and theory is the same.

A SD70Ace with say 4300hp can pull say 1500t on the flat.  Two of them with combined 8600hp could pull 3000t on the flat. That's easy.
Now we thow in grades. Those two SD70Ace's can only pull say 2300t up a 1% grade. If we though in curves as well the tonnage is further reduced. This is all still pretty easy.

Now we get a bit harder. Suppose we have an SD70Ace and a GP50. The SD70Ace we know has 4300hp and can pull 1500t. The GP50 let's say is 3600hp and can pull 1000t. Most people would think that we have 7900hp and can pull 2500t on the flat. Wrong. The SD70Ace develops it's max tractive effort at say 21mph but the GP50 develops it max tractive effort at 15mph. What this means is that the GP50 cannot pull it's max rated load at the same speed as the SD70Ace so the tonnage that can be pulled by both is actually say 2100t. The prototype has all sorts of tables that state what tonnage can be pulled by what combinations in what territory.

What this means, to bring the post back to RailPro is that pure hp and train tonnage can be meaningless unless the loco's are all the
same in their capabilities. I really don't know what RailPro could do with that information. RailPro's load sharing seem to mimic the above dynamics of differing capabilities well but even that can probably only go so far. Until our models start becoming equipped with drives that are not directly coupled between the motor and the wheels we'll never properly have prototype dynamics.

I'd love to see a proper 8 notch throttle with proper loadup/ rundown / coasting and proper braking. I almost finished reworking a design for one years ago.

- Tim.

William Brillinger:
....Not to mention the issues of selective compression of train size and tonnage. It would be nearly impossible to automate the dynamics of a train on the throttle in a way that would 'feel' right on every layout.

But, given smooth transitions from Notch 1 to 8, [Notch Up], [Notch Down], and a [Coast] button, it would certainly be easy to replicate the behaviour.

Alan:
Tim,

I am probably bias because I write software (part of day job) that works with relational data points and tables. I'm sure the code could be written to accurately (good enough) recreate actual train movement. Getting the layout data points would be the real challenge. I am implementing an occupancy detection system that is much more granular than most layouts have - 33 detectors in 150' main. It reports train direction as well. If a RP 2.0 system did exist that could do the math, I may have a detection system that could feed it the necessary curve/grade/direction info.

Manually controlling the train while also manually controlling the sounds seems like a half baked solution to me. Better than no independent control I suppose.

Just dreaming  :-\

Alan:
The occupancy detection I referenced earlier:

G8B4Life:
No problems with dreaming Alan, I'm still dreaming too. More on that later.

I do have to say, I've read your detectors and breakers. Nice job on them (though you did have to choose just about the most inaccessible IC in this country for the breakers).

Now, unless I'm reading your thinking wrong, it sounds like what your describing is having the software determine what notch (sound) it should be in regardless of throttle setting.  That could possibly be done by monitoring the current draw but I imagine you'd get wildly different experiences on grade vs flats. Load tables, inputting the tonnage (hp could be predefined when setting up the LM) and data points around a layout would help that but I think you might be the only who would implement it. Interesting concept though.

My dream? I'm still dreaming of my almost perfect system. Back in the day when I was experimenting with torque couplings I had an almost perfect system; I could physically be in notch 8 (the motor spinning at full rpm) with the train at walking pace with a heavy load behind it. Speed matching or load sharing was completely automatic as part of the drive train. If only I had sound and a coast button back then I would have had it.

- Tim

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