The Museum's curator cuts out around
the stay bolts that secure the inside
sheet to the outside sheet. During
operation, water between the sheets
is heated by combustion in the firebox.
The lower portion of the side sheet on
the right side of the firebox has been
removed allowing the back side of the
wrapper sheet to be inspected. Several
small cracks were found radiating from
stay bolt holes.
With today's regulations - and the genuine desire to operate in a safe and efficient manner - there are some parts of the locomotive boiler that are being replaced. Inside the firebox, the side sheets were repaired with a mixture of gas and early electric welding techniques, perhaps as many as 90 years ago. Unfortunately, this presents challenges for the certification and sustainable operation of the locomotive. Even if these repairs could be dissected and the boiler approved for operation, these repairs of unverifiable workmanship could present a problem during the next 1,492 days of operation, and require remedial repairs in the middle of an operating season.
The new side sheet sections are welded
into the boiler. The holes will soon be
tapped for new stay bolts.
Brand new sheets were purchase, fitted, drilled, and installed. A modern electric welding machine was used to install the plate and the holes are being tapped for new stay bolts. While working inside the firebox, some of the rear sheet seams were welded to improve performance and reliability when the locomotive is converted from coal to oil.
Replacing the lower portions of the side sheets inside the boiler is just one of many tasks required in the process of rehabilitating and restoring former Northern Pacific Railway steam locomotive 924. This intensive process will take approximately two years of effort. Already, dozens of volunteers have contributed more than 750 hours, and the Museum's curator is committing 85% or more of his work day to the project. It is just the beginning, but a measurable effort for a project that began less than four months ago.