How Efficient Were the "Big Three"?

[NW Mailing List]

Most revenue service steam locomotives maxed out at about 6% thermal
efficiency. Energy of fuel used versus drawbar horsepower.  A modern AC
diesel is about 30%.  It gen diesel about 20%.

The most efficient revenue steam locomotives where the Andre Chapelon
compound passenger 4-8-0s in France.  High single digit thermal
efficiency.  There where prototype steam engines that hut thermal
efficiency over 10% but steam was dying and it wasn't pursued.

Best Regards
John Rhodes


On Fri, Oct 6, 2023, 10:31 AM NW Mailing List <nw-mailing-list at nwhs.org>
wrote:

> Greetings,
>
> In the rudimentary research I've done on N&W's big three (J, A, Y6/a/b),
> I've gotten the impression that they were among if not the most efficient
> steam locomotives built in the United States, in some cases outperforming
> the first-generation diesels. But exactly how efficient were they? From
> what I've heard the maximum fuel efficiency of a steam locomotive is about
> 15%. Did any of the big three have the abil
>
> Eli Santinity to reach this efficiency level?
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