[Traindude]

When specifying boiler length for these new parameters, do we include the length of the water space around the firebox and combustion chamber, or just the distance between the tube sheets/plates?

[darwins]

Distance from the front tubeplate to the backhead. (Total length of boiler barrel and firebox.) For a sloping backhead it would ideally be the distance to the top, but realistically small differences are not going to change much.

[pschlik]

steamer_ctn, on 27 April 2025 - 11:46 PM, said:

To activate this functionality, the following two parameters need to be added to the ENG file. I had thought of also activating MSTS stock, however after looking at the default Scotsman, it appears that there will be issues with values in MSTS ENG files. For example the Glass Height is shown as 10 in the Scotsman, as there are no UoM, OR assumes this to be 10m, a bit unrealistic!

I would guess the most likely thing going on there is that MSTS assumed the glass was measured in inches, so you could add a STFReader.UNITS.DistanceDefaultIn to provide the same results as the 'Distance' units, but where no units given means inches instead of meters. But the UNITS enum is running out of space since it was set up bitwise (why? you do bitwise when you need the ability to say something fits into multiple categories simultaneously, but a number is either going to be a length or a temperature, never both) so adding more units, especially for one off cases, isn't going to work for very long. That problem goes well beyond water sight glasses anyway.

[cesarbl]

A quick fix for the UNITS enum with few side effects would be to change the enum to be long-based instead of int-based (the default), but I agree that it makes no sense to use one bit per unit, since a field can't have two units at the same time.

[darwins]

steamer_ctn, on 28 April 2025 - 02:51 AM, said:

For example, see the 3rd post in this thread, which indicates that the glass was up to 18in long.

On p24 it says of the loco in the incident "The water glass itself was a glass tube about 12 inches long"

I didn't find the 18in, but steeper gradients and longer boilers will both need longer glasses. USA has both steep grades and some very long boilers so 12in or even 18in doesn't seem impossible.

[pschlik]

As I showed on the Big Boy, the thing had two staggered glasses, so each glass might be 12 inches but because one is higher than the other you effectively get that 18 inches or so. I suppose you just tell OR it has an extra long sight glass, but in the cab view limit the display range of one glass to be 0-0.66 and the second to be 0.33-1.0?

[steamer_ctn]

pschlik, on 28 April 2025 - 08:56 AM, said:

I would guess the most likely thing going on there is that MSTS assumed the glass was measured in inches, so you could add a STFReader.UNITS.DistanceDefaultIn to provide the same results as the 'Distance' units, but where no units given means inches instead of meters. But the UNITS enum is running out of space since it was set up bitwise (why? you do bitwise when you need the ability to say something fits into multiple categories simultaneously, but a number is either going to be a length or a temperature, never both) so adding more units, especially for one off cases, isn't going to work for very long. That problem goes well beyond water sight glasses anyway.

Thanks for the suggestion.

If I used these MSTS values, I would probably assume that they are in inches as you have suggest. I could then force an inch conversation when the value is read.

However this is risky if our assumptions are not 100% correct, and potentially it perpetuates bad data entry. At the moment, I am thinking that I would rather get users to enter new valid data to ensure that the function works correctly.

[Laci1959]

Hello.

I think the inch will be perfect. This is against the OR principle, but I think we could make an exception here.
In Hungary, the size of pipes is given in coll, which is the German name for the inch. Source: Wikipedia.
I was shocked when I was calculating the surface area of ​​the smoke pipes and fire pipes of my steam locomotives.

Sincerely, Laci1959

[Traindude]

Another thing that I just thought of -- on many of the larger, latter-day locomotives, the crown sheet is sloped downward towards the rear, while smaller and older locomotives, the crown sheet is flat/level. Do we need any new parameters for defining the separate heights of the front and back of the crown sheet? Would it make any difference?

[steamer_ctn]

I have updated the code to allow variation due to gradient when the parameters on the attached diagram are defined. The diagram comes from the UK DoG locomotive, and these could be added to the ENG file for testing.

The calculation of these parameters has been simplified from the perspective that sloping crown sheets, etc have not been included.

So the question now becomes, how easy will it be for users to find and include these values in their configurations?

NOTE: If you run these changes at the moment, they will probably read high, as the existing water level logic is reading high compared to these values. This will need tuning, and may slightly change the locomotive performance (ie water level values might be lower), however I would like to see some other values for these parameters before making any changes.

Attached thumbnail(s)

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[Laci1959]

steamer_ctn, on 30 April 2025 - 11:06 PM, said:

So the question now becomes, how easy will it be for users to find and include these values in their configurations?

Hello.

It seems that the values ​​A C, D, E. I will post it in a Facebook group for two professions and then I will see.

Regards Laci1959

[darwins]

C and D are almost impossible to find for most UK locomotives. A is available for boilers with a straight backhead, but not always available for sloping backheads like the one in the diagram. However the additional distance of total length, which is more readily available should not greatly change the result. B is readily available for all boilers. E is not readily available, but we can assume that 6in will suffice for boilers up to 20ft in length with values increasing up to 9in or 10in as boilers reach 30ft in length.

[Traindude]

I just thought of something else -- in this case how the water level on grades relates to Southern Pacific's Famous Cab-Forward articulated locomotives.

On regular locomotives, which have the cab, firebox and water glass at the back end of the locomotive, the water level increases on an uphill grade and decreases on a downhill grade. The cab forwards, on the other hand, have their boilers effectively "flipped" in direction relative to the boilers on regular locomotives, since the cab, firebox and water glass are now in front instead of in the rear. It stands to reason that with the boiler "flipped" in this manner, the water level would decrease on uphill grades and increase on downhill grades.

Feels like we should make an allowance for this.



Incidentally, the grades also created some problems in the flow of fuel oil to the burner. Normally, the oil flows to the burner by means of gravity. On a more conventional oil-fired locomotive, this is of very little concern, as the distance from the tender is relatively short -- the oil only has to travel the length of the drawbar, cab and part of the firebox to get to the burner. With the cab forwards, the oil had to travel the length of the boiler in order to reach the burner, so this creates some difficulties on steep uphill grades. It has been said the solution was to seal the oil tank and pressurize it with around 5-20 PSI air pressure to give the oil a boost on uphill grades...but that's a discussion for another thread...

[steamer_ctn]

Traindude said:

1746237573[/url]' post='318174']
I just thought of something else -- in this case how the water level on grades relates to Southern Pacific's Famous Cab-Forward articulated locomotives.

Thanks for that. What changes would need to be done to accomodate this situation.

Perhaps you can keep a list of these “variations” so that we can look at possible changes that we may need to consider.

It should be noted, that not all scenarios may be worth the coding effort to try and take them into account.

[Weter]

Yes, it seems very important note, so maybe, *eng-files have to include notation, that this water glass is mounted in front half of boiler (rear can be default).
And also, if cab-forward design has more obligate features, they could be taken in account altogether, by CabForward (1) flag, IMO.