[NickonWheels]

Thanks, Gerry. Looking forward to the announced update... Well-placed hidden message about physics indeed.

[steamer_ctn]

I have been investigating the code, in particular the parameters that define the Diesel Engine (Prime Mover) and both the BASIC and ADVANCED configurations appear to use the "same" type of parameters.

In broad terms, they can be grouped as follows:

i) Oil Pressure - appears to be for display purposes only

ii) Temperature - appears to be for display purposes only

iii) Diesel fuel - appears to shut the engine down if it reaches zero, and also can alter the weight of the locomotive, and friction as it varies.

iv) RPM - alters the time taken for the engine to reach full power, and also to decrease power.

So currently for performance accuracy it appears that only the diesel fuel and rpm parameters are "important".

Given the acceleration time of the engine impacts the initial application of tractive, the change in rpm rate parameters can have a marked impact on the performance of the locomotive, especially when starting. I have done some research to try and accurately identify the change in RpM values for the main prime movers, but apart from some anecdotal information, I haven't found any solid information.

The information that I have found seems to suggest that the 645 prime mover takes approx 15-20 seconds to reach full rpm, whereas the 710 prime mover seems to be able to do it in about 5 seconds. Looking at a few ENG files, it appears that there is a wide variety of parameter settings for the RpM change rate.

I was hoping to find some manufacturers information that would shed some light on these values.

Does anybody in the community have any information that would be helpful?

[NickonWheels]

steamer_ctn, on 12 February 2020 - 11:13 PM, said:

iii) Diesel fuel - appears to shut the engine down if it reaches zero, and also can alter the weight of the locomotive, and friction as it varies.

Even though I never tested weight & friction change on diesels before I noticed a bug with the Davis lines in ORTS freight animation settings. I´ve tested Scott´s bell-ringing 2-8-0s which have ORTS tender-specific freight animations but the friction value at 5mph and full coal/water is lower than the appropriate .wag line FullORTSDavis_A ( 347.21lb ) but not as low as the empty weight line EmptyORTSDavis_A ( 245.49lb ). In fact it´s about 345lb which can´t be right even when not taking Davis B/C into account.

[hugoakio]

I'm also having problems with tractive effort with the 53 version of Open Rails MG. Diesel locomotives are so weak in the startup, something out of reality.
I can garantee that my locomotive have all parametes related to power correct because i match the operator manual parameters with the .eng file.
Also the behavior in a known route are weird. Since I worked at that real railroad and recreated this with the original grade project, and before the 53 the behavior are identical to the real thing, i believe that is something wrong in the last version.

[Csantucci]

hugoakio, on 13 February 2020 - 10:22 AM, said:

I'm also having problems with tractive effort with the 53 version of Open Rails MG. Diesel locomotives are so weak in the startup, something out of reality.
I can garantee that my locomotive have all parametes related to power correct because i match the operator manual parameters with the .eng file.
Also the behavior in a known route are weird. Since I worked at that real railroad and recreated this with the original grade project, and before the 53 the behavior are identical to the real thing, i believe that is something wrong in the last version.

Please test with the Unstable version.

[steamer_ctn]

NickonWheels, on 13 February 2020 - 08:04 AM, said:

Even though I never tested weight & friction change on diesels before I noticed a bug with the Davis lines in ORTS freight animation settings. I´ve tested Scott´s bell-ringing 2-8-0s which have ORTS tender-specific freight animations but the friction value at 5mph and full coal/water is lower than the appropriate .wag line FullORTSDavis_A ( 347.21lb ) but not as low as the empty weight line EmptyORTSDavis_A ( 245.49lb ). In fact it´s about 345lb which can´t be right even when not taking Davis B/C into account.

The difference you are looking at is approx 0.6%, which could be caused by rounding or conversion factors.

The other point to consider is that some differences will occur due to temperature variation as well.

So in short, the value on the HuD may not be "exactly" the same as the value shown in the ENG file. Some minor variations will occur due to either of the above factors.

If the difference is significantly larger then the above difference then there maybe an issue to look into.

[steamer_ctn]

If anybody has been using the test methodology that I have described above, and is interested, I have added some additional information in regard to other locomotives in use by Norfolk Southern. So it should be possible to run similar tests for them if they have been adjusted correctly.

[scottb613]

NickonWheels, on 13 February 2020 - 08:04 AM, said:

Even though I never tested weight & friction change on diesels before I noticed a bug with the Davis lines in ORTS freight animation settings. I´ve tested Scott´s bell-ringing 2-8-0s which have ORTS tender-specific freight animations but the friction value at 5mph and full coal/water is lower than the appropriate .wag line FullORTSDavis_A ( 347.21lb ) but not as low as the empty weight line EmptyORTSDavis_A ( 245.49lb ). In fact it´s about 345lb which can´t be right even when not taking Davis B/C into account.

Hi Nick,

I'm no expert on this subject - is there an issue with my config - or is it the overall ORTS physics the cause for your concern ? I used FCalc to come up with the various friction values used on my stuff...

Regards,
Scott

[NickonWheels]

scottb613, on 14 February 2020 - 03:49 AM, said:

Hi Nick,

I'm no expert on this subject - is there an issue with my config - or is it the overall ORTS physics the cause for your concern ? I used FCalc to come up with the various friction values used on my stuff...

Regards,
Scott

Thanks, Scott

This problem is independant of whatever values are used, for example I replaced your data with something calculated myself and got similar faulty results. Looks like a bug in the code somewhere...

[R H Steele]

steamer_ctn, on 13 February 2020 - 10:43 PM, said:

If anybody has been using the test methodology that I have described above, and is interested, I have added some additional information in regard to other locomotives in use by Norfolk Southern. So it should be possible to run similar tests for them if they have been adjusted correctly.

Thank you for the information...excellent resource, very much appreciated. Have you been able to find the complete report?
I noticed you were able to determine what locomotives belonged in the groups identified in the abstract. That is helpful, again thanks.

I have one question...wouldn't you agree that the SD70ACe made for Pilbara duty is an outlier? Locomotives designed for that work were heavier and had other modifications that made them suitable for mine haul duty that were not present in those used by the Norfolk Southern.