[Rj Zondervan]

Hi all,

First of all, if the website administration feels this question can better be put in another board, I'm sorry.

At the moment I'm writing engine files for a historic Dutch electric locomotive built in France. The model was created by a friend of mine who I usually write engine files for.

For this new model we decided it was best to give it a behaviour that would be as realistic as possible with the possibilities that OR gives us, including the use of traction tables/diagrams.

Now, we found out that this locomotive has 9 throttle positions (of which 4 are not meant to use below a speed of approximately 65 kph, because the motors are put in parallel configuration instead of in serial configuration), and put in the data that were collected by the locomotive manufacturer, with some extrapolation as the diagrams that we got our hands on did not show data for very low speeds (<~25 kph) or speeds that were not supported for the specific throttle position (the highest 4 throttle positions would have blown out the circuit brakers for speeds lower than approximately 65 kph).

However, even at the low throttle positions, OR seems to disagree with the given traction characteristics, as might be caused by the fact that the extrapolation resulted in a minimal traction of 150kN at low speed with the smallest throttle configuration (I know it sounds weird, but this is the data that was provided). OR seems to cut down the value to something that might seem more realistic for more modern types of traction. However, when trying to move around the diagrams for various throttle positions, I noticed something strange: when I forgot to move the 0kN-column for 0% throttle and the column with 150kN was moved to the 0% throttle, this line (and those of the other low throttle positions) seemed to be read correctly (although, off by one throttle position), but at higher throttle positions it seems to disregard the table again, resulting in the locomotive not reaching it's top speed.

Is there some way to get this type of traction diagram working correctly, or might it help to provide the (original) traction diagrams to someone in the OR development team in order to get locomotives with these configurations (there are more Dutch and French locomotives with similar diagrams around) running correctly?

Regards,

Robert

PS: In the attachments I provide a set of tried tables:
 NS1100_tractiontable.txt (12.56K)
Number of downloads: 513
This table provides the throttle configurations in the order serial low to parallel high (as recommended by the manufacturer) without extrapolation at the higher throttle positions
Result of this table: at 19% throttle (or 18.5 according to the configuration in the engine file), the locomotive gives 1500N of traction instead of the 150kN stated below, and when increasing the throttle the traction is extrapolated somehow in ways that do not correspond the table.

 NS1100_tractiontable-extrapolated.txt (12.97K)
Number of downloads: 488
This table provides the throttle configurations in the order serial low to parallel high (as recommended by the manufacturer) with some extrapolation at the higher throttle positions
Result of this table: at 19% throttle (or 18.5 according to the configuration in the engine file), the locomotive gives 1500N of traction instead of the 150kN stated below, and when increasing the throttle the traction is extrapolated somehow in ways that do not correspond the table.

 NS1100_tractiontable-switched.txt (12.34K)
Number of downloads: 450
This table provides the throttle configurations in the order parallel low to serial high (an order that is not recommended by the manufacturer)
Result of this table: traction remains 0kN at all times when the locomotive is at standstill, no matter the position of the throttle

[dajones]

I'm not sure, but I think the throttle values need to be fractions between zero and one instead of a percentage.

Doug

[R H Steele]

I don't think they will work, even if they are formatted correctly.

I'm in the process of writing up a bug report...I think any traction or tractive tables (ORTSMAXTractionCurves) do not work properly.
There may be something wrong with the way Advanced Adhesion was coded.
I've been testing the ORTSMaxTractive Curves and during testing it was determined that the use of this block reduced the "power to the rail" at Run8 to considerably less than the normal 80-90% range. It was proportionally lower at all other power notch settings.
Using the default MSTS engine files the power to rails at notch8 was in the normal range and proportionally correct at all other power notches.
Adding the ORTSDieselEngines block ( via OpenRails folder, include eng file and Common.inc folder ) the power to the rails at notch 8 was also in the normal range.
Adding the ORTSMaxTractive Curves block to the mix reduced the power to the rails at notch8 considerably ( 50% range +/-)
Also and this is to the OP point...the tractive curves did not respond as expected.
It would be beneficial to have explained how these two parameters are handled by the Advanced Adhesion section.ORTSTractionCharacteristics
ORTSMaxTractiveForceCurves

[Rj Zondervan]

dajones, on 04 August 2018 - 02:34 PM, said:

I'm not sure, but I think the throttle values need to be fractions between zero and one instead of a percentage.

Doug

Ah off course... Should have noticed that (and probably would have noticed that if it wasn't my own code :wallbash: ), the locomotive now runs just fine. Let's put this error in the old "blindness for own failure"-department that traps quite a lot of developers and programmers :sweatingbullets:.

R H Steele, on 04 August 2018 - 02:49 PM, said:

I don't think they will work, even if they are formatted correctly.

I'm in the process of writing up a bug report...I think any traction or tractive tables (ORTSMAXTractionCurves) do not work properly.
There may be something wrong with the way Advanced Adhesion was coded.
I've been testing the ORTSMaxTractive Curves and during testing it was determined that the use of this block reduced the "power to the rail" at Run8 to considerably less than the normal 80-90% range. It was proportionally lower at all other power notch settings.
Using the default MSTS engine files the power to rails at notch8 was in the normal range and proportionally correct at all other power notches.
Adding the ORTSDieselEngines block ( via OpenRails folder, include eng file and Common.inc folder ) the power to the rails at notch 8 was also in the normal range.
Adding the ORTSMaxTractive Curves block to the mix reduced the power to the rails at notch8 considerably ( 50% range +/-)
Also and this is to the OP point...the tractive curves did not respond as expected.
It would be beneficial to have explained how these two parameters are handled by the Advanced Adhesion section.ORTSTractionCharacteristics
ORTSMaxTractiveForceCurves

Hmm, your story makes for interesting reading, especially as the locomotive now seems to run fine (okay, I did not check everything exactly to the diagrams, but the behaviour is now close to what is expected), but I agree that some explanation about the handling of these parameters would be beneficial.

Thanks for your input! I'm going to sit in a corner to feel ashamed for a little while for not noticing such a stupid mistake, and finish up the engineering of this locomotive.

Regards,

Robert

[copperpen]

The fact that an unaltered MSTS eng file gives proper TE readings suggests that it is not the advanced adhesion at fault, but the overly complicated method of using multiple TE curves, one for each throttle setting.

Remember the KISS principle.