One of the ways the A-Line Husky Stack differs from the Athearn Husky Stack is the walkway platform configuration. As shown here the platforms have different sizes on each size.
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The A end (above and lower left) have two different sizes of upper platforms
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while the B end (above right and below) have the same size of upper platforms.
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Also noticable in these photos are the replacement brass details. They consist of Stanchions, Liftrings, Locator boxes and Load guides.

Husky Stack Walkways with Brass details - Aline Car