Why were there N&W coal cars on Sherman Hill? Because a few customers west of the Rockies thought that the coal mined on the N&W had enough qualities which western coal did not have to justify the additional transportation costs.
That said, however, I doubt that many of the battleship gons went over Sherman Hill because those gons were designed to be unloaded at dumpers, and I don't believe that the West had many if any at all. Indeed, they were rather scarce in the East being used primarily to transfer coal from rail into ships or barges.
Therefore, whatever coal was carried westbound over Sherman Hill in N&W cars was carried in hoppers, or perhaps, bottom-dropping gons.
Tim Gilbert
It was meant in jest Tim. That is what was meant by the smiley face. I too, doubt many battleship gons went over Sherman Hill.