[jmlozano]

Good afternoon.
Please, look at this screenshot...Figure in the circle. It represent the current superheat temperature, ins'n it? Why is it negative? It seems superheater is full of ice, nor of steam....

Bye.

[steamer_ctn]

In the OR code this value is zeroed @ 0 deg Fahrenheit.

However 0 deg Fahrenheit = -18 deg Celcius, so hence the metric HUD shows a negative temperature when the locomotive is at rest.

Apart from appearing to be an odd figure at rest, it should work correctly.

[jmlozano]

Degrees Farenheit?
If 32º F are 0º C, -18º F are -27,7º C...
I don't know if I understand well your replay.

[steamer_ctn]

0⁰ F = -18⁰ C

[jmlozano]

Yes, then...Boiler is full of ice!
What I mean is: this figure is not representative superheater temperature. Something must be bad. You know, I suppose, temperature inside tubes superheater is, with locomotive running, always more than 212 ºF (100 º C ). For that reason, it is very odd this indicator be -18º C.

Bye.

[copperpen]

Until a locomotive begins to move and use steam, there is no steam in the superheater tubes and a high temperature would result in burning the tubes. Once the locomotive is moving steam is passed through the superheater and temperature begins to rise. I agree that -18C is a very low temperature for a locomotive with a fire burning, it should be higher, even if it is only heating air inside the superheater. There is a possibility however that the superheater model is based on a type that actually closed off the superheater when steam was not passing through, in which case it would be low at the start of a locomotive duty, but if at a station stop would be fairly high due to residual temperature in the superheater system.

[xavivilla]

I think that a locomotive, even if it is turned off (no fire in the home), any part of the locomotive, should be at least at room temperature.
It's a humble opinion

[copperpen]

A quick test shows that the minimum superheat temperature is directly linked to the setting of the throttle which is definitely not correct, close the throttle and temp drops to zero degrees F regardless of how hot it was originally. This has been so since at least the release of stable version 1.2

[steamer_ctn]

 xavivilla, on 28 April 2018 - 01:45 PM, said:

I think that a locomotive, even if it is turned off (no fire in the home), any part of the locomotive, should be at least at room temperature.

 copperpen, on 29 April 2018 - 07:55 AM, said:

A quick test shows that the minimum superheat temperature is directly linked to the setting of the throttle which is definitely not correct, close the throttle and temp drops to zero degrees F regardless of how hot it was originally. This has been so since at least the release of stable version 1.2

IN OR Superheat temperature is model in a similar fashion to the information produced in various test reports. (See attached graph example from the BR V2 Test report)

This graph shows that superheat temperature increases with the amount of steam consumed by the steam cylinders. Thus decreasing the throttle will decrease the steam consumption in the cylinders, and hence the superheat temperature will decrease also with the throttle

Whilst the graph is not shown for values lower then 12000 lb/h of steam consumption, it could be extrapolated to 400^oF at 0 lb/h of steam consumption, which in effect is 0⁰F Superheat Temperature. Whilst superheat temperature may not exactly go back to 0^oF, for the ease of modelling in OR it does go to 0^oF. This does not produce undue error and impact upon the OR performance.

Attached thumbnail(s)

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[copperpen]

I figured that the cause was the simple option, no steam use equals zero superheat controlled by the throttle. I have also done a bit more thinking on this, and accepting that superheat will be zero if the engine has not been used for a period of time, equally it will not be zero if the engine has been in use, and steam remaining in the superheater will not immediately lose all of its gained heat either when the usage rate goes down. Therefore rather than have the temperature reduction controlled by the throttle it should be controlled by a countdown timer that starts when the throttle is reduced or closed. As a starter I suggest losing X degrees of heat per minute spread over 10 minutes after which the temperature will be zero, with X representing the percentage lost. In the case of a partial throttle closure the same countdown timer can be used with the end figure being the temperature for the current steaming rate.