[R H Steele]

Filed Bug Report >> Bug #2023083 >> please see this thread >>> posts 16 and 17

When maximum sanding speed is set to 15mph, OR will indicate sander is blocked at approx. 5mph. However, force hud indicates wheel slip at approx 31%. Using keyboard to shut sander off force hud then indicates wheel slip at around 50%.

[pschlik]

Alrighty, I somehow survived the process of making a pull request for this. There were many mistakes. I made 7 commits, 6 of which I reverted because of messing around (ah github, why not at least hide my shame?). But hey, that 7th one did what I had in mind. I'm guessing next time will go more smoothly since I learned how a few things work in the process of breaking everything.

I managed to assemble a pretty clean solution to this, the changed code takes up a lot less space to do the same thing (but with better handling of the max sanding speed, of course). Unfortunately, it looks like making the sand blocker disable the sanding sound is more involved than just editing a few functions in one file, so that will have to wait for another time.

For now, I am going back to my .eng and .wag file editing hole. There are features I want to add to the code, but I'm trying to avoid further scope creep on my engine/wagon physics until after I am ready to release that to the public. I may still contribute some "5-minute" bug fixes (this fix took me all evening) before then.

[R H Steele]

pschlik, on 06 June 2023 - 07:31 PM, said:

Alrighty, I somehow survived the process of making a pull request for this. .... I may still contribute some "5-minute" bug fixes (this fix took me all evening) before then.

http://www.elvastower.com/forums/public/style_emoticons/default/lol.gif Amazing how those "5 minute" fixes stretch into hours...anyway, much appreciated...we'll see what happens, thanks for your effort. I'm learning a little about the code by reading your explanation ( in the other thread ) along with examining the code example. Yep, sound is something else, from all I've read in other threads.

Regards, Gerry

[pschlik]

Looks like it's part of Unstable now, feel free to try that activity again and make sure adhesion stops being increased when sand gets blocked.

[darwins]

A question about real trains. Is there such a thing as a fixed maximum speed for sanding to work? Thinking to most of the locos I am familiar with, there is nothing to stop you applying sand at any speed. Having said that, I imagine as speed increases sanding might become less effective as the sand might get scattered about more. (It always seemed strange to have this parameter in MSTS, how appropriate is it for new OR eng files?)

[Jonatan]

No I don't see any physical reason why sanding would just "stop" above a certain speed in real life. It might be a modern thing of computerised locomoives to prevent wasting sand, but the traditional sander is just a box that dumps sand from a tube on the track when the operator activates it - and stays active until the operator deactivates it.

So I ask the same thing why it's in OR? MSTSs parameter didn't realy seem to do anything, thank goodness.

[pschlik]

Current North American designs will inhibit the use of manual trainline sanding (this is the type of sanding OR simulates) above a certain speed (for example, 7 mph on the GE Dash 8) in order to reduce sand consumption. This mode of sanding applies sand on every single locomotive using an MU cable signal, which uses a lot of sand and becomes particularly ineffective once the train is moving. Meanwhile most of the rest of the world isn't running trains with 5 locomotives connected together, so there's no reason to make sand work over the MU cables, and the problem of wasting sand is sidestepped.

At higher speeds, automatic sanding during wheel slip (not implemented in OR) and lead axle sanding (not implemented in OR either) can still be used, so you aren't entirely out of options. A moving train, particularly a heavy American thing, will clean the rails as it moves along (again, not in OR), which means the lead locomotive has the worst adhesion and thus it's more useful to sand the lead unit than any other unit. The sand the lead unit puts down will also help the adhesion of other units behind it, so throwing down more sand on those units wouldn't do much.

Of course, without any of those features, I just don't set a speed limit on sanding so I can pretend I have lead axle sanding at any speed. Workarounds like that aren't great, there's definitely room for improvement...

• Changes in track conditions along length of train (big change, probably beyond me for the moment)
• Automatic local sanding based on wheel slip % (small change, I have some ideas for this)
• Manual local sanding by either adding new lead axle sand control or reworking current control to apply to lead only (medium change, adding new controls is a bit involved, also useless without changing track conditions)
• Change sand sound and sand indicator light to only work if sand is actually applied (medium change, would probably need to be reworked to accommodate automatic sanding anyway)

[Weter]

Congrats with successful PR!
One more OR contributors.
No matter, 6 or more trials, most important - enjoyment with result, Your personal enjoyment.

[R H Steele]

With regard to opinions & questions about maximum sanding speed and sanding stopping in real world --- I've always relied upon this information supplied by copperpen ( in this thread post # 6 Sanding speed )

Quote

Now sanding. In the real world when wheelslip occurs the first thing you do is close the throttle to stop the wheelslip. Then if needed apply sanding and open the throttle again. sanding becomes ineffedtive at high speeds because the sand gets spread far thinner on the railhead, so is only really useful at slow speeds. OR does read the sanding line in the MSTS eng file, so I have my speed set at 15mph. Over this speed the effectiveness of sanding is greatly reduced so requires greater attention to be applied to the handling of the train when climbing hills. To me, this makes running the sim much more interesting than setting the throttle and sit back to watch the train chug over the hill.

...and using the OR unstable version with the new code added the sanding operates as expected...also the sound cuts off correctly.

[darwins]

I would like it to work as Copperpen describes. That is:The effectiveness of sanding reduces gradually as speed increases.There is nothing to stop you using sand at any speed - just that you are wasting it if you are moving too fast.Other than as described above for US and similar diesel locos working in multiple, there should be no sudden cut off between sander working and sander not working.

[R H Steele]

Of course, that would be the best case to be hoped for. However, most all the MSTS eng files have an inexhaustible supply of sand.
comment( infinite sanding time )
MaxSandingTime( -1 )
I wonder if OR parses this line...if so would be good to have OR ignore this and provide a prototypical amount of sand available for use. More coding?

So I suppose for now substituting a definite speed limit after which sanding ceases because in reality it is ineffective is the best solution we presently have.

[Weter]

Hello.
Sorry, I likely misunderstood, but I see two different things, mentioned in last post by Gerry, having nothing common with each other.
1. Is sanding efficiency's fading with speed growth: now it looks like sanding "cutoff" in greater speeds, than specified.
2. Is defining sand deposits on given unit (including possibility to infinite them)
So, why should them be tied in game? Why forgive player's carelessness, if he just turns sanding on and wastes it all?
On real locomotives driving practice it's proven much time back: impulse sanding is overall more efficient, than continious.
(And there can be automatized function for impulse sanding application on more modern locomotives) I don't know, have US locomotives automatic sanding cutoff with speeds, higher, than predefined, though.
Also, railroad instructions order to stop sanding, while passing switches, as it will damage switch gear with thin sand, being spread around.
And one more: modern stock do have EP sanding definitely, so it can be activated (deactivated, I think, too) by some safety systems in addition to driver's control.
More frequent case - emergency stop knob, which cuts power, opens brake pipe and applies sand, plus sounds horn. In some models, crew member can pull-out emergency system triggering ring and jump off locomotive, or run away to diesel room with it on finger - as a proof, that all measures were used to stop the train.

[pschlik]

If you want sand to reduce in effectiveness as speed increases, use ORTS ( ORTSSanderSpeedEffectUpTo ( x mph ) ) I have no clue why this isn't mentioned in the manual, but using that causes a linear decrease in the friction sand provides, starting at a factor of 1 at 0 speed, and dropping to halving adhesion when speed is 'x' mph. (This means that sand will become completely ineffective around a speed of x/2.)

[Weter]

ORTS() within engine section?

[R H Steele]

pschlik, on 08 June 2023 - 05:27 AM, said:

If you want sand to reduce in effectiveness as speed increases, use ORTS ( ORTSSanderSpeedEffectUpTo ( x mph ) ) I have no clue why this isn't mentioned in the manual, but using that causes a linear decrease in the friction sand provides, starting at a factor of 1 at 0 speed, and dropping to halving adhesion when speed is 'x' mph. (This means that sand will become completely ineffective around a speed of x/2.)

So you can confirm that the ORTS parameter is currently coded --- applies directly to the condition that Darwin brought up, that's a nice surprise! I have never seen that mentioned anywhere in the threads. To Weter's question I would assume it is used in the eng section of the engine file...would be good to know for sure.

Edit: Did a quick search of the threads and found two other times the parameter is mention ( although not specifcally in connection to sanding )
Post #36 and Post #18
These two posts ( if I'm reading them correctly ) show the parameter to be used in the eng section of the engine file.