Talk:Southern Railway Ps-4 class

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DYK	December 6, 2015

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Which USRA pacific class was the Ps-4 based on?

I've found internet sources that state both the USRA Heavy and the USRA Light Pacifics as the direct predecessor of this class. Which is right? I *think* the correct answer is the Light, and I've edited the USRA Light Pacific page to reflect this, but it's far from clear. Does anyone have better information about this? Formerly, the USRA Heavy Pacific page listed the Ps-4 as a descendant, but the Ps-4 page contradicted this. So now they're consistent, but possibly incorrectly. --Dibujaron (talk) 23:30, 30 April 2019 (UTC)[reply]

I think the Ps-4 is much more similar to the USRA Heavy Pacific than it is to the USRA Light Pacific. Comparing the data on the Ps-4 I've compiled from various sources (mostly the Price and Ranks & Lowe books), the locomotives weigh 304,000 lbs, versus (as stated on the respective pages here) 300,000 for the Heavy and 270,000 for the Light. The Ps-4 cylinders match the Heavy and are larger than the Light. The Ps-4 grate area is almost exactly the same as, or even larger than, the Heavy, and larger than the Light. I think the only notable parameter where the Ps-4 is more like the Light is driver diameter (both 73"), with the Heavy having larger drivers (79"). N'Awlins Contrarian 03:18, 29 April 2024 (UTC)[reply]