ErickC, on 05 February 2020 - 03:57 AM, said:
anyone running locomotives made by either me or Tyler Bundy is going to find them completely immobile after updating to any version of OR that uses the new diesel model.
To make sure that we are on the same page, what version of OR are you running?
Earlier in this post, I posted links to two test locomotives that I built for testing (post #69 & #75), and demonstration purposes. Both of these locomotives have a
BASIC (no traction curve included - sudo MSTS configuration) and an
ADVANCED (with full traction curves specified). I have just retested these two units in the latest
Unstable version, and they both appear to move correctly, so in theory your units should also run without any problems. These locomotives were tested against a BR test report, and produced outcomes in OR very close to those measured in the test reports.
The ORTSDieselEngineMaxPower parameter is not essential for performance, but more so for accuracy of display performance.
ErickC, on 05 February 2020 - 03:57 AM, said:
For my part, I'm perfectly happy to send sample locomotives along if it might be helpful.
Can you rerun your locomotives in the latest unstable version, and if still presenting the issues you described, then you can send me a sample to look at?
R H Steele, on 05 February 2020 - 10:33 AM, said:
For Peter >> the only aspect of these posts I can comment upon concerns the above...it is true that prior to the recent diesel code changes the OR Diesel eng definition would work without the ORTS Max Tractive Curves being present...now it will not. Locomotives using the ORTS Diesel Engine definition without ORTS Max Tractive Curves display zero power. The Max curve set must be present for the OR diesel eng defintion to work. I think this should be examined. ( I'm using the default MSTS engine file - OpenRails folder - and Common.inc folder.)
See my comments above.
Include files, and also data layout in files may also be creating a potential issue, and thus would need to be investigated as a separate issue. This issue is related to the order in which OR reads data input files, and assigns default values if a required parameter is missing (see this
post in regard to the comments on "data sequencing").
darwins, on 05 February 2020 - 12:54 PM, said:
Thinking about those locos that we can't get the data for - then perhaps it is good to think about a diesel electric as being a (fairly) constant horsepower machine over most of its operating speed range.
I think that the diagram that Darwin was posting would have looked something like the diagram attached.
This diagram is very interesting, and important for our understanding of diesel locomotive performance. The key points are that the traction motor has three zones of operation, ie Constant Torque, Constant Power, and High Speed Zone. The speed points at which each zone changes is firstly the "speed of maximum continuous effort", and the "maximum velocity of the locomotive".
One interesting point to note about the traction curve is that it doesn't go to zero force when the locomotive is operating above its maximum velocity speed, however in BASIC mode OR currently sets tractive force to zero, and in ADVANCED mode, the tractive curves should reflect the difference in the curve.
darwins, on 05 February 2020 - 12:54 PM, said:
I find it easier to work things out in terms of power and then calculate force later as tractive force curves have steep gradients and rapid rates of change.
Most diesel manufacturers supply the rated tractive force and speed characteristics of the locomotive (see the manufacturers data sheet provided in post #112), and typically this is the force applied to the track by the locomotive. Any power values tend to be highly speculative, and depending upon where they are measured, as well as the downstream efficiency losses, they could lead to erroneous specification of the locomotive.
Hence for anybody striving to achieve the most accurate outcome in OR, as they are a known reference point on the traction curve specified by the manufacturer, and also based upon my testing to date, I would suggest that the force figures be used instead to calculate the maximum power delivered to the rail.
ErickC, on 05 February 2020 - 01:55 PM, said:
I'd be making guesses, which is why I let OR handle it, since it did a really good job. The basic tractive effort model is pretty good for any pre-microprocessor locomotive.
I agree, and if the correct parameters, and values are used then OR should give a good performance result (as confirmed by the earlier test locomotives provided).
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