Effects of Pressure Altitude on Steam Engine Efficiency

[NW Mailing List]


While on vacation on in AZ, we were paralleling some rails from Winslow to Flagstaff.  Knowing that water boils at a lower temperature at a relatively lower pressure, how did this principal apply to the operation and performance of a steam engine operating in lower pressure altitudes (higher elevations)?

Christopher J. Bunsey









> On May 26, 2021, at 10:21 AM, NW Mailing List via NW-Mailing-List <nw-mailing-list at nwhs.org> wrote:
> 
> As followers of this blog know, I volunteered to explore potential supply options for a N&W Roanoke Shops HO-scale sign that might be sold through the N&W Historical Society commissary.  This is a status report:  some good news and some less good news.  
> 
> Miller Engineering confirmed that they will be reissuing the “diesel-era” style N&W Roanoke Shops sign this summer!  That’s the good news.  I requested a wholesale price (and min. order size) on the reissued diesel-era sign in case the Society might have an interest (perhaps via a pre-order process).
> 
> Bad news:  Miller Engineering has no plans to issue the steam-era sign unless someone wants to commission a run of at least 500.   I requested a price, but anticipate the minimum order size would be prohibitive.  
> 
> I have been in touch with an HO-scale modeler who can make an unlighted steam-era N&W Roanoke Shops sign for us.  Might be an interesting option.  Lettering would be in red.  Superstructure in black.  I am waiting on a call back on pricing for a multi-sign run.  Original set up would be about $100.  After that, price is based on the cost of materials plus 20%.  
> 
> If anyone knows of a potential source for obtaining the support structure in photo-etched metal, please let me know as the red plastic sign itself could be attached to the metal superstructure and that would probably be more realistic.  
> 
> Bill D
> N&W Steam Only
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