Centerplates and Springs

Center truck assembly

Center truck assembly

George Sapp inspecting center plate

George Sapp inspecting broken center plate

 Our paid and volunteer staff have had to remove the center truck assembly from the #2 Shay locomotive, in order to repair a cracked center plate.  The entire truck assembly was pulled out into the yard, where our Railroad Restoration Leadworker, George Sapp, was able to get a good look at it.   The center plate appears to have failed at a previous weld.  It can’t be repaired again, so we have ordered steel and we’ll machine a new part in the Railtown shops.   In the meantime, we can poke around and see what else can be repaired while we’re waiting.

The assembly contains 30 springs, which sit between the bolster and the undertruck frame.  This portion of the machine bears  35-40 tons at any given time, so it is reasonable to assume that these springs will need to be replaced routinely.  To our eyes, the springs seemed a bit “squished”. 

 George Sapp measuring springs on the center truck.

George Sapp measuring springs on the center truck.

Measurements  were taken, in order to help us determine whether we should replace these parts while the truck is disassembled. 

George placed a call to the California State Railroad Museum library.   In the Lima Locomotive Works Collection, Librarian Cara Randall located drawings for truck bolsters for this class of locomotive.  The drawings specified a  spring length of 6 inches.  The worse spring was 1/8″ shy of that, not very much wear at all.  Therefore, it has been determined that the springs are ok for re-use.

George Sapp and Librarian Cara Randall examing Lima drawings

George Sapp and Librarian Cara Randall examing Lima drawings

 View of Lima drawing of truck bolster.

View of Lima drawing of truck bolster.

So, at this point, we are waiting for our steel order to arrive.  Then we can begin machining a new center plate, and be back on track fairly quickly, we hope!  Stay tuned.

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