[copperpen]

Tractive effort = power. Tractive effort curve all fall as speed increases. While I totally agree that as speed increases and valve events are shortened a steam engine gains in efficiency, and gains in the amount of power produced at the rail per pound of steam used due to that efficiency, it is not a power increase in the true sense of the word.

While Kuju did not give us true valve events to adjust, nor did they give us different valve types to use, they did at least get the power curve right alongside the steam usage curve with the highest amount of power coming from a high reverser with as high a throttle setting as adhesion will allow. This then allows steam to be used inefficiently, but at as high a pressure as possible for the maximum travel of the piston.

[Matej Pacha]

Guys, the situation about the steam physics is pretty simple: Now we have something that at some points match the MSTS physics and what really doesn't match the real world behavior. If we are talking about a near future, we should focus on the ORTS physics matching the MSTS physics, using present ENG data. Any improvement of the MSTS physics is not necessary - we already have better model to implement but it requires a new ORTS ENG file format and much more work to do.
If you want to help, you can build a mathematic or pseudo-code description of the MSTS physics. I can update the physics code but not before the new signalling is fully implemented. When the team decides that the bug-fixing phase is over, we'll start the new physics implementation process.
No offense, but in any kind of technical matter, I prefer to use the terms of physics instead of simplified forms of ambiguous meanings. If I do, I never write this: "effort = power". Thanks.

Matej

[copperpen]

If I do, I never write this: "effort = power". Neither did I.

[copperpen]

If copperpen will read this I do not know but.........

The statement "tractive effort = power" is NOT correct, I have found this is a VERY common missconseption amongst railway people. For some idea of the differnce between the two physical properties I will use this example. A locomotive may have a tractive effort of say 25,000lbs at 60mph and a TE of 50,000lbs at 30 mph. The tractive effort is clearly double at the lower speed, the power though used in both cases is the SAME it being 4000bhp. The loco is NOT more powerful at the slower speed inspite of the tractive effort being higher.


Sorry, but tractive effort is a measure of the power of a locomotive. So is the IDHP which is what you are referring to, however, this can only be at its maximum, the same as the boiler HP capacity. The only way to reach this at any kind of speed is to reduce the valve settings thereby reducing the time steam is admitted to the cylinders, using the expansion properties of steam. By this token, tractive effort, the power placed at the wheel rail interface gets lower as speed increases, which is why the IDHP figure came in to use because it better reflects the power of a locomotive.

I think that this is what KUJU were thinking with the two lines MaxPower ( 1500kW ) and MaxForce ( 26927lbf ), these taken from the default Scotsman eng file, MaxPower being the IDHP and MaxForce is the Highest tractive effort figure. Where they went wrong was in the way they coded this in relation to the throttle, reverser which do work properly, and steam chest pressure which does not.