It's not a caboose, although it looks like a baywindow one. It's a boxcar with oversized doors and tracks. It's a roofwalk, but there aren't platforms. Question 1, where did you get a 1/400 set of train cars? it looks more like 1/160 to me.
About ten years ago there was a really nice article in one of Kalmbach's annuals, I think it was "Model Railroad Planning" concerning this subject and I'll find it and invite Aaron or Kelly or Matt to provide a linky. Quite a remarkable series of planning decisions involved in the transfer of goods and personnel from rail to ship.
This is a nice dio for sure. I recently was a part of a renovation of an historic pier on the wharf in SF, Pier 1 which you'll see if you care to Google. One fact is that the roll-up doors on the shed are 40' apart, which is the length-over-coupler of the AAR standard box car of the time.
Edit: interesting. The ship scales at almost exactly 10 boxcars, which would be 400 feet. But the APA is 450 feet. At Revell scale, it's 10% too small, so there you have it. Ship has been identified as a Haskell Class/ ne. Revell Montrose Class APA, but where did you get those trains?
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