Gene, the original Intermountain O scale models represented the
two types of seams. The IMWX HO scale model only represents the
crimped seam and I think this was repeated in Intermountain's HO
copy of that model. I've tried to find out myself the answer to
your question about who used which type of seam.

A builder photo of a SP B-50-18 shows that the rivet seams to
the left side of the door show the edge of the steel panel of
their right, while those to the right side of the door clearly
show the edge of the panel to the left of the rivet seam. I'm
pretty sure this car uses a lap seam.

On the other hand, a close up photo of a B-50-19 shows a raised
vertical strip with each rivet seam. But it looks like the edges
of the panels are oriented the same way as the B-50-18.

The original IMWX kit had W-corner posts, and the kit represents
the crimped seam that would be found with this end. When an S-corner
end version was made, they did not revise the side panels and did
not really make much of an effort to properly represent the end
either (the rivet seam attaching the end to the side is terrible,
but now can be fixed with Archer rivets).

Tim O'Connor


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