Talk:Power at rail

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The reason that maximum power at rail is rarely given for steam locomotives is that any steam engine can for a short time develop enormous power by "mortaging the boiler". That is, by using steam faster than the boiler can generate it.

However, sometimes figures are quoted for drawbar horse power, which is measured over a long time/distance using a dynamometer car. Maximum figures for British locomotives are around 2,000 dhp.

I don't have a reference for this information - if any railway engineers can find one though....

--Exile (talk) 19:27, 30 April 2008 (UTC)


 * You make a good point - however I would expect the maximium power at rail to be proportional to the boiler pressure - therefor power at rail would be related to max boiler pressure, and the fastest rate a which coal could be shovelled in (this I would expect to be limiting?)
 * Using steam faster than the boiler could produce it would reduce the tractive effort (as the boiler pressure decreases) and so would not actuall represent the maximum continuous power..
 * Im not an expert on steam locos though so don't have the references you see - the second point would be relevent to the article Continuous tractive effort
 * It's possible that the additional complexity you describe (compared to say a diesel engine of limited rated strength) may make a separate steam article about performance a good idea...

merge proposal
I'm suggesting merging this article into tractive effort as a subsection of a section of "tractive effort (rail)"

Please discuss this proposal on the talk page of Tractive effort