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[quote user="feltonhill"] Since you mention it...... The 4400 horsepower figure for the N&W J was first used in a specification list dated March 11, 1941, seven months before the first J was completed Oct 20, 1941. It is a Rated Maximum Horsepower figure, and is apparently based on a maximum evaporative capacity (N&W's words) of 11,500 gallons/hr, or about 95,833 lbs/hr total evaporation, BP of 275 psi. I ran this through the Baldwin estimating method that was favored by N&W in that era, and came up with a calculated drawbar HP of 4410 at 35 mph, using an evaporation rate of 74.4 lbs water/SF of DHS/hr, producing a total figure including FWH of 95,833 lbs/hr. These figures are too close to be coincidental, so I believe I correctly used N&W's method of estimating. Moving ahead to 1982, I found NW Mechanical Dept Drawing for 611, no number but the date is 7-28-82, initialled by M.D.B. This drawing replicates exactly the Nominal Top Speed - 85 mph and Rated Maximum Horsepower - 4400 words and figures from the March 1941 specification sheet. This is  virtually the same drawing as published in the ASME booklet.  Based on the above I have to assume that (1) 4400 is not an actual rating, and (2) it is based on a 275 psi J, not 300. Just by way of a tickler, the maximum DBHP for a Class J is not 5,028 at 41 mph.  N&W never said it was.  The often cited DBHP curve was calculated using the Baldwin method.  It was neither actual nor maximum at 300 psi.  N&W so stated and cited its estimating method. Hope this helps   [/quote] feltonhill, thank you for your correction and clearing this, lars
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