Mal,
I await your article but have to admit I am dubious. There are a number of discrepancies between the picture bcp posted and the picture Jeff posted on the high bridge.
First there are only six windows on the side and should be seven.
Second the baggage door is too far from the end, it should be only the distance of one window as seen in the DSP&P picture.
Third the SL&M 23 has nine clerestory windows while the C&S has 13.
Fourth the belt rail on the C&S ends at the end of the windows while the SL&M the belt rail runs from the end to the baggage door.
I await seeing your article.
Ken Martin