Probably a little early, Kevin, but just say your chief of engineering liked to experimenet and was ahead of his time with many ideas.
I think the main thing that brought the fixed low and high bunks in was improved off-track loading and handling machinery. I'm guessing this was something like the early Payloaders with big gripping tines instead of buckets. Those came into service mostly post-1960, but there were some other methods used that were more traditional. The goal was to transport more raw wood per car, like similar increases in car design.
The low bunks came first AFAIK. The high racks added more security against logs falling off or becoming dislodged. IIRC, the Class 1 did more line haul work from loading areas to the mills and required this from the loggers in order to handle this traffic safely. I believe it was NP that did this, but wouldn't surprise me if the requirement was more widespread.
Mike Lehman
Urbana, IL
I have three flat cars I installed these onto. I am set in 1954.
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Are they similar enough to an earlier style, or did I goof up the timeline again?
Silly me. The log bunker design is so obviously basic I assumed they had been around forever. I should have known the details would bite me.
-Kevin
Living the dream.
The tall one is roughy 1960s on, the short may have been a little earlier, put post-WWII. Both appear to be welded construction and fixed. Earlier versions tended to be rivited and moveable, so tended to be more prone to damage and needing repair. The welded ones held up better over the long term.