Hardly surprising - that was depression era thinking, before many developments pushed the envelope. It's the only figure I had at hand, though.....

dave

Greetings All!

Gary Bensman asked that I post this information which he retrieved from Lima engineering files housed at the museum in Lima.

S160:

With 1, 765 sq.ft. of heating surface their boilers put out a maximum of 30, 000 lph. By calculations not field testing.

Allegheny's:

With 7, 240sq.ft. of heating surface their boilers put out a maximum of 100, 116 lph by calculation.
Now, the calculated boiler HP is 4,813 and the calculated locomotive horsepower (by the original file) is only 4, 740. In reality they repeatedly tested out well in excess of 7, 000hp and once topped 8, 000hp. So, given the underestimated lbs per sqft (previously mentioned) and the underestimated hp of the boiler and machine.... just what did they put out? No less than 100, 116 lph and likely quite more.

Cheers All, Jason

"Boiler HP" (a rather non-descriptive unit) is calculated by dividing the steam production rate (100,116 lbs/hr for the H8 above) by a constant rate of 20.8 lbs/Indicated HP. That's where the 4,813 (I)HP comes from. However, most modern locomotives operate at a ratio of 16 lbs/IHP or less. This ratio would give something on the order of 6,257 IHP, which is closer to what would be expected of the H8 over-the-road. Keep in mind, an H8 could generate far more steam per hr than 100,000 lbs. An N&W J managed that and more during tests.

Also keep in mind the term HP is meaningless without an adjective, in this case indicated which is measured at the cylinders. Drawbar HP is measured at the rear of the tender (unless it's PRR and...well, you know how that goes).

Perhaps poorly worded..... but that was my point exactly!

Cheers