I would guess that the BNSF track charts and profiles are pretty accurate on the grades over Stampede. The main east of Yakima is fairly flat. There is a bump bewteen Satus and Mabton -- not really much, and between Kiona and the Columbia River, again not much,although an underpowered train can have some trouble (WCRC did tend to be underpowered). Between Yakima and E'burg, the main does closely follow the Yakima at water level, usually within spitting distance. There is a long siding, unsignaled, at Wymer where BNSF likes to hide empties. For those who yake photos, the canyon segment offers numerous good shots in spetacular surroundings and SR821 is usually within sight of the railroad.

Yes, the tunnel soes have a hump, summit near the center. In the ancient days of steam, crews, I am told, called it "Stampede Hell". One can imagine what it would have been like with the soft smokey coal NP used! I do remember a few trips through the bore on the old North Coast Limited and Mainstreeter and the heavy fumes gathering even in the dome cars!

All being told, the ideal solution is a new tunnel, but I'm not holding my breath on that one.