[copperpen]

One small (big) problem with save/resume using steam locomotives. The steam generation data is not saved and therefore on resume starts at a very low level so a save while moving at speed is not possible without losing massive amounts of boiler pressure.

Is it possible to add tender fuel and water levels to the debug data. These would allow actual consumption to be seen against totals in the tender.

[cjakeman]

 copperpen, on 30 August 2013 - 03:10 AM, said:

One small (big) problem with save/resume using steam locomotives. The steam generation data is not saved and therefore on resume starts at a very low level so a save while moving at speed is not possible without losing massive amounts of boiler pressure.

Boiler pressure is already saved and restored by OR, so there must be something else going on here. Would you raise a bug report please? Can you give an example (preferably using an activity from Settle and Carlisle)?

 copperpen, on 30 August 2013 - 03:10 AM, said:

Is it possible to add tender fuel and water levels to the debug data. These would allow actual consumption to be seen against totals in the tender.

Don't see any sign that these levels are maintained by the code yet, so that's one for the wish list. Better, I think, if we solve any issues with steaming first.

[cjakeman]

 Lindsayts, on 29 August 2013 - 10:02 PM, said:

On further though Re the above a more usefull arrangement would be a pressure line in the debug info.
The Line would read something like.......

Pressure:
Boiler pressure: 210.7 psi Valve chest pressure: 147.2 psi Backpressure: 15.7 psi

All done. It's available now in v1727.

[copperpen]

 cjakeman, on 30 August 2013 - 11:59 AM, said:

Boiler pressure is already saved and restored by OR, so there must be something else going on here. Would you raise a bug report please? Can you give an example (preferably using an activity from Settle and Carlisle)?

Boiler pressure is saved, as is all other data with the exception of the steam generation figure. This is restored at a very low level. In the engine I am currently using before the save the figure was roughly 46000, on restore of the save this was 15500 approx. With cylinder steam usage at 43000 approx. This resulted in a rapid drop of pressure from 220 to 190 before getting the throttle closed. Recovery from that drop takes a while.

I will run an activity on the default Settle route and raise a report as requested.

Edit at 20.33 GMT: Bug report raised, log and two screenshots included.

[copperpen]

While running the requested test on the default S&C I noticed something that is not correct. Opening the throttle causes an immediate noticeable increase in the cylinder steam usage figure as well as an increase in steam chest pressure. The steam usage figure increase with throttle is wrong. The cylinder usage figure should be derived from the piston speed over the swept volume of the cylinder, modified by the cut-off setting.

The throttle of a steam engine works the same way as any other vehicle throttle. It increases the amount of usable energy available to be used. In the case of the steam engine throttle it increases the steam pressure available to be used by the cylinders ( the steam chest pressure figure). The cut-off setting then determines how much of that steam will be available for each stroke of the piston (the cylinder steam usage figure).

[Lindsayts]

 copperpen, on 31 August 2013 - 06:02 AM, said:

While running the requested test on the default S&C I noticed something that is not correct. Opening the throttle causes an immediate noticeable increase in the cylinder steam usage figure as well as an increase in steam chest pressure. The steam usage figure increase with throttle is wrong. The cylinder usage figure should be derived from the piston speed over the swept volume of the cylinder, modified by the cut-off setting.

In MSTSSteamlocomotive.cs it is derived that way see lines 153 (SteamUsageFactor) and line 583 (SteamUsageLBps), the code does not take into account the effective opening of the inlet port, this means the steam consumption is more than double what it should be at short valve travels. I arrived at this conclusion when comparing the actual steam flows of PRR K4s 5399 with OR set up for a K4s.

Quote

The throttle of a steam engine works the same way as any other vehicle throttle. It increases the amount of usable energy available to be used. In the case of the steam engine throttle it increases the steam pressure available to be used by the cylinders ( the steam chest pressure figure). The cut-off setting then determines how much of that steam will be available for each stroke of the piston (the cylinder steam usage figure).

Lindsay

[captain_bazza]

You mean something like this?

We know names of these particular sharks in waiting, don't we!?


Cheers Bazza