planetmaker wrote:

That highly depends upon the definition used for "horse power". Quoting wikipedia:
"Metric horsepower began in Germany in the 19th century and became popular across Europe and Asia. The various units used to indicate this definition (PS, CV, pk, and ch) all translate to horse power in English, so it is common to see these values referred to as horsepower or hp in the press releases or media coverage of the German, French, Italian, and Japanese automobile companies. British manufacturers often intermix metric horsepower and mechanical horsepower depending on the origin of the engine in question."

IMO this FS entry can be considered invalid and the difference (if at all) small enough to be neglected for all practical purposes. The author should assume metrical horse powers for the English translation or direct to documentation which states clearly which kind of "horse power" is meant by the newgrf specs (they don't tell as far as I could establish).

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mb wrote:

Nah, I´ve also read that Wikipedia article. Using anything like "hp" is a total mess, a fact you may notice when stepping on the bugs and inconsistencies in that very article. IMO, the only reasonable way to go would be to change to SI units internally, and thus avoid shortcomings like this.

Granted, the difference in this case may be "small" (ref article!) but OTOH, the number (in PS) is often used as a hallmark in German engine class names, a feature which totally gets lost if e.g., a "V160" doesn´t have 1600 PS but 1578, and a V200 gets 1972 instead of 2000 PS.

This comment was imported from FlySpray: https://bugs.openttd.org/task/3280#comment6871

planetmaker wrote:

But if you use the "metric horse power" the difference is exactly zero. That's the way easiest change for all concerned parties. There's nothing in the specs which state that it's the wrong horse power. Your turn to argue why you HAVE to chose a horse power with a different definition IMO.

This comment was imported from FlySpray: https://bugs.openttd.org/task/3280#comment6872

mb wrote:

If you did read said article, cited by yourself, you´d know that British "hp" isn´t identical to either German "PS" nor "metric horse power", the latter being identical to German "PS".

Being a German yourself, you possibly don´t know that the term "Europe" in a Wikipedia article written by a Brit (or American) does exclude the UK, automatically. And indeed, the only "hp" unit understood in the UK is the original British "hp", correctly called "bhp" (brake horse power) which is based on (non-metric) units pound (lbf) and feet (ft).

1 bhp = 550 ft * lbf /s = 1.014 PS (DIN)
1 PS (DIN) = 0.986 bhp

And o/c, that´s the power unit used in TTD, TTDPatch and OTTD, together with that other non-metric unit, the imperial mile, rather than the km.

Apart from this particular problem, it would be advantageous to make the complete shift to SI units (we´re already using kN in tractive effort calculations) to get a coherent approach with regards to translations (German locomotives getting their 3000 PS, British getting 3000 hp) and with a correct representation of unit numbers.

Also notice that from january, 1st 2010, all non-SI units are inadmissible in the EU. Why should we stick to a bunch of old-fashioned non-metric units when this causes extra trouble both in code and in translations?

This isn´t nit-picking, BTW.

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mb wrote:

[SI units] And electrics would eventually get correct kW! Where on earth is power of electric locomotives still being measured in PS or hp?

This comment was imported from FlySpray: https://bugs.openttd.org/task/3280#comment6874

Rubidium wrote:

Under 'Game Options' -> 'Measuring units' select 'SI'. That way you'll get kW, kg, m/s instead of HP, tonnes and km/h or mp/h. I wouldn't solve the translation 'issue', but if you want that to be correct you'll probably need a few dozens extra explanations/calculations of HP.

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planetmaker wrote:

I do share the view that conversion to an internal representation in SI units is desirable, but it is to my knowledge done at least partially. Then - possibly for translations - a conversion factor to the desired units could be provided - and set - by the translators, though.

Despite that, the article states that the English word "horse power" is not well defined and the usage of any of the definitions is as good as the other. So, first of all, it needs a clarification what units "horse power" as mentioned in the newgrf wiki refers to exactly.

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mb wrote:

Seems that the general problem is understood now, and I do fully agree with Ingo´s last post first two sentences now.

@remko
Didn´t spot that feature until now, sorry.

Anyway, what´s the difference between "metric" and "SI"? SI is indeed metric (derived from mks).

OTOH, SI is differing between "base units" (metre, kilogram, second, ...) and "derived units" (newton, watt, ...). I.e., you´re already using derived SI units in that option. So, why is speed shown in m/s? Km/h is perfectly SI (by using the SI prefix "kilo", resp using the SI compound unit "km/h"), but is more common for the speeds in question.

And there are more inconsistencies with that game option:

- the "US ton" is not equal to the "metric ton". Instead, the US "short ton" is 907 kg.
- the US "horse power" is not equal to the German "PS". Instead, american "SAE hp" is equal to British "bhp",
- the US unit for tractive effort is not "kN" but "lbf" (1 lbf = 4.4482 N)
- in "SI": if you allow only "base units" (kg, m, s) then you may not use "kN" but have to express it in "m*kg/s²", possibly together with a prefix. If not, you´d be allowed to use also derived and compound units, e.h. km/h.

Well, that´s for now. :)

This comment was imported from FlySpray: https://bugs.openttd.org/task/3280#comment6877

frosch wrote:

Once upon a time... there was a transport simulation game. It specified speeds of trains, road vehicles and ships in units of 1/1.6 mph resp. 1/3.2 mph. It used a factor of 103/64 to convert from mph to km/h for GUI purposes.
One some fine day (on 2006-04-08 to be precise) a young fellow crossed the scene and said: "What bollocks is this all about? Specifiing stuff in 1/1.6 mph? Why don't you use km/h in the first place?"
And so it was done. The 1/1.6 mph usage was abandoned and the values were reinterpreted as km/h, which was then converted to mph for GUI purposes using the factor 5/8 if someone actually wanted to see such units.
But... what did happen? Suddenly from everywhere all around dwarfs turned up and shouted: "Oh, waily, waily! What did ya do to us! All our trains are running at wrong speeds. What silly train runs at 99 or 129 km/h, eh? We spent years on drawing some pixels, and now everything is broken!"
And so all the dwarfs threw theirself on the poor young fellow and kept on bashing him ... and well, after 8 months (2007-01-30) they had tortured him enough. And the broken fellow agreed, that 1/1.6 mph is a totally sane unit and is nothing near km/h.

And what does this small story tell us?

- Internal units will never never be changed. Everyone expects their behaviour exactly as it is, everyone tunes every single value until it shows what he wants, and actual math or physics or similiar does not matter at all. (Btw. there is also not a single benefit in using SI units, as the game units are totally arbitrary anyway).

Sorry, without a story:
- Units will never be specific to single languages.
- Units will never be converted using floating point arithmetic with 16 digits precision. Therefore a 1.4% change does not affect gameplay or anything at all.

So if you care about a German engine having 3000 PS then just specify 3000 hp, be happy about the 3000 PS in the German translation and don't care about British units. Personally I cannot believe anyway that every single instance of that engines has exactly 3000 PS with 4 digits precision, so no sane British engineer would have said, oh that engine over there has exactly 2958 hp.

Period. Task closed.

This comment was imported from FlySpray: https://bugs.openttd.org/task/3280#comment6878

frosch closed the ticket.

Reason for closing: Won't fix

we are not rocket engineers

This comment was imported from FlySpray: https://bugs.openttd.org/task/3280