In my response I considered the sills as part of the body structure The underframe being the bolsters and the needle beam. I'm in 100% agreement with you on the break in dates of steel. Once steel is introduced the whole idea of what's in the underframe begins to change.
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On May 31, 2010, at 7:37 PM, soolinehistory wrote:
--- In STMFC@..., Roger Hinman <rhinman@...> wrote:
Iron or steel? Hardly. Look at the end of the draft sill where it shows next to the coupler; you can see the annual rings of the wood!
The needlebeam support is wood whereas everything in the under-frame by this time was iron or steel, hence painting it a different color made some sense...
Since draft sills were some of the first parts of the underframe to be converted to metal (those and body bolsters, which are metal on these cars) the sills above them are undoubtedly wood also. The construction with the iron faced wood buffer block with a iron strap dropping below the sills to both tie them together and support the coupler shank is also very typical of an all wood underframe. The 1904 date of the photo is just a couple years too early for major amounts of steel in underframe construction.