Booth Kelly Lumber Co. #7
This builder’s photo shows the beginning of upgrades that Willamette would be making to their design. Notice the dry pipe now beginning at the smokebox instead of the dome. This signifies superheating of the steam. Construction #8 was built with the Ball balanced D valves, but is also the first Willamette with superheat. The D valves were not satisfactory with the superheat, and the D valve cylinders were changed out with piston valve cylinders. Willamette was the second of the 4 geared locomotive manufacturers to adopt piston valves. Climax beat Willamette in this regard by several months on their 70 and 80 ton class C engines.