Working out the 'power' rating for steam locomotives

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AndyLandy
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Working out the 'power' rating for steam locomotives

Post by AndyLandy »

I'm interested in modelling some older steam locos using NewGRF, but I'm struggling to work out how to work out what I should be setting for power and top speed.

For modern diesel & electric locos, power ratings and top speeds are all specified, but I understand that it's rather more ambiguous for steam.

The only stat that Wikipedia ever seems to mention is tractive effort. Even then, it rarely states if this is starting, continuous or maximum TE. Nor does it state what reference velocity is used.

What models do people use to try and make their trains reasonably realistic? Is there a way of modelling an actual TE curve in-game?

Thanks!
michael blunck
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Re: Working out the 'power' rating for steam locomotives

Post by michael blunck »

AndyLandy wrote: I'm interested in modelling some older steam locos using NewGRF, [...] Is there a way of modelling an actual TE curve in-game?
Maybe this could be helpful?

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AndyLandy
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Re: Working out the 'power' rating for steam locomotives

Post by AndyLandy »

Hi Michael,

Indeed. I've had a look through that thread, and I'm fairly confident that I can use the numbers I do know to work out what the coefficient of tractive effort (prop. 1F) should be for most of my locomotives. The challenge I have is trying to work out what are suitable values for power (prop. 0B) and max speed (prop. 09). As far as I can tell, there's no direct correlation between TE and power, and I'm stumped if I can find enough information to derive one from the other. Top speed is even more of a mystery.
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andythenorth
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Re: Working out the 'power' rating for steam locomotives

Post by andythenorth »

I've gone looking before for steam locomotive power figures for Iron Horse.

It's not a simple number :)
This discussion is pretty good.
https://www.trainorders.com/discussion/ ... 10,3012475

And in even more depth, Al Krug's article is great, but long :)
http://www.railway-technical.com/trains ... iesel.html

For Iron Horse, I now just pick stats that get the gameplay performance I want for each engine. Playability > realism. ;)
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wallyweb
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Re: Working out the 'power' rating for steam locomotives

Post by wallyweb »

Another source is if you are after max speed, feed the engine model or number into the YouTube search bar. The description below the video often gives some specifications.
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Re: Working out the 'power' rating for steam locomotives

Post by michael blunck »

AndyLandy wrote: The challenge I have is trying to work out what are suitable values for power (prop. 0B) and max speed (prop. 09). As far as I can tell, there's no direct correlation between TE and power, and I'm stumped if I can find enough information to derive one from the other. Top speed is even more of a mystery.
You could theoretically calculate power and speed for steam locomotives (see attachment).

However, to do so you´d need a lot of technical details (mostly unknown for a specific design), and the results won´t give you a good idea how a certain locomotive would behave under real conditions.

Best thing is to find real values for a given locomotive model in railway books.
steam-calculation.png
steam-calculation.png (23.42 KiB) Viewed 3297 times
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Re: Working out the 'power' rating for steam locomotives

Post by Snail »

Top speed is also limited to the number of revs/second of the driving wheels. For early steamers (i.e. before 1900, or anything narrow gauge) it shouldn't really be any higher than 4; for more modern steamers, it should be capped at around 5.5 (in no case higher than 6).
In other words, a steamer with larger wheels will be allowed to run faster than one with smaller wheels.
The French Narrow Gauge Train Set is now released! Get it here
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acs121
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Re: Working out the 'power' rating for steam locomotives

Post by acs121 »

As i would do, you can pick from very similar looking locomotives. Try to find a vehicle set with a similar locomotive and pick the power from it.
Note that until 1890 approximatively, locomotive power isn't more than 1000 generally.
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