Tonnage reduction with temperature falling

NW Mailing List nw-mailing-list at
Mon Dec 17 09:33:15 EST 2018

Don’t think temperature affected thermodynamics of the locomotives that much.  As long as the water in the tender didn’t freeze (and that happened on an A-tank on the Columbus district once, I’m told) the feedwater heaters still did their job.

Ed King

From: NW Mailing List via NW-Mailing-List 
Sent: Sunday, December 16, 2018 10:01 PM
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Subject: Tonnage reduction with temperature falling

I was under the impression that the reason the tonnage went down with temperature was thermodynamics of water evaporation to get the needed pressures of steam. The point about oil and grease viscosity makes good sense as well. 

Mike Shockley  

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