Tuesday, December 30, 2014

Steam begins to simmer

Museum's Curator of Collections peers
from the 924's firebox door opening.
Rehabilitation of locomotive 924 is underway!  Some important progress has already been achieved with significant and positive news emerging since bringing the locomotive into the Conservation and Restoration Center this past fall. 

Inside the boiler barrel, scale is removed
from the inside of the tube sheet.
The first objective was to inspect the inside of the boiler, which required the boiler tubes to be removed.  To allow for tube removal, some other appliances and components had to be removed first including the master mechanic’s front end (helps direct exhaust and improve combustion), smoke box front, steam dome lid, and throttle valve.  Once that work was completed, then all the boiler tubes were removed to allow scaling and inspection of the boiler barrel interior.  The process has yielded some wonderful news: the inside of the barrel is in great shape.  Some of the witness marks used to lay out the rear tube sheet can still be seen!

Boiler sheet thickness measurements
were entered directly into a spreadsheet.
With a clean boiler barrel and access to the firebox, the team measured the thickness of the boiler sheets using an ultrasonic thickness tester.  Measurements were taken along a grid and provided data that was entered into a spreadsheet, which performed preliminary "form 4" boiler calculations.  The form 4 is what the Federal Railroad Administration uses to evaluate a request for approval to operate a locomotive boiler, and at this point in the project it represents a sort of acid test as to whether an historic locomotive is feasible to rehabilitate.  And the 924 successfully buffered the acid: preliminary calculations suggest an operating pressure of approximately 170 pounds per square inches, and without any major boiler work, provided there are no serious issues on the exterior.

A Federal Railroad Administration
inspector examines the 924's firebox.
During the annual inspection of SCPC 2, inspectors from the Federal Railroad Administration were able to make a brief visit to the 924.  They reviewed the initial work plan and looked inside the firebox.  Ensuring the Federal inspectors remain apprised of the work plan and progress is also an important part of the project.

An area of firebox side
sheet is being removed
to allow for replacement.
Certainly there is work to perform on the boiler that is desirable and will help ensure a full 1472 days of operation before the operating approval expires.  One area of attention involves the side sheets inside the firebox.  This area received some type of repair many decades ago, and the repair was performed with gas welding.  Today, such repairs are generally performed with electric welding and to ensure the integrity of the vessel, the old repair is being removed and replaced with a new patch.  this process will also require the stay bolts restraining this area to be replaced, in all numbering about 200 items.

So as 2014 draws to a close, the 1899-built locomotive 924 has a wonderful New Year to look forward to, and your support can ensure that the work continues!  Please consider a tax-deductible contribution to the "steam program campaign". All contributions will be used to rehabilitate and restore locomotive 924.

Cutting around stay bolts in the firebox side sheet.


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