Question/Dilemma about High Bridge Construction...?

[NW Mailing List]

Could it possibly be that there were plans to double track the  bridge?  I 
recall hearing something about that at one time.   Alan  Cox
 
 
In a message dated 5/7/2014 9:18:56 A.M. Eastern Daylight Time,  
nw-mailing-list at nwhs.org writes:

Guys
Can you help unravel this mystery?
Why are the High  Bridge Rails off to one side of the towers now as opposed 
to directly in the  center of the towers originally as seen in
the Vail pics attached  below.

Bob Flippen

Moderator:
http://nwhs.org/mailinglist/2014/20140507.hb.3.jpg
http://nwhs.org/mailinglist/2014/20140507.hb.4.jpg
http://nwhs.org/mailinglist/2014/20140507.hb.5.jpg
http://nwhs.org/mailinglist/2014/20140507.hb.22.jpg
------------------------------


In Vail's photos, it appears that the  bridge spans were laid in the center 
of the towers, as is clearly shown in  the first attached file
(and many of his other photos).  The girders  of the span run right across 
the two stiffeners (or whatever they are) in  the center of the
cross-girder at the top of the bridge  bents/towers.

BUT...  today the bridge spans run along one side  of the towers, as 
clearly shown in the 2nd and 3rd attachments.  The  spans do not run
directly over the two stiffeners in the center of the  cross-girder.  And, 
in fact, in Vail's photo of the new and old bridge  together (4th
attached), the girders of the new bridge clearly rest on  the outside of 
the tower.  This makes sense since the bridge was  constructed to
support two tracks.

So what am I missing???  I  looks like the constructed spans on which the 
steam crane rode to install  the top section of the bents and the
next bridge spans isn't in the same  position as the final bridge spans!  
Were these spans temporary to  support the installation, and then
moved?  Nothing is mentioned of  moving the spans later, and that seems 
like it would be a waste of time and  energy.  And Vail's photo of the complete 
bridge shows the spans in  place on the towers as we see them today.  I'm 
obviously missing  something!





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