After receiving information from the Mt. Rainier Scenic that confirmed the sand dome sheet metal height as being 17.5 inches, it was decided to determine how tall our smokestack needs to be to for the diamond to clear the top of the sand dome, and look good at the same time. After measuring the boiler, a full size-drawing was made on the floor, with pertinent information included. With the dome profile in place, a full-size cardboard diamond profile was placed on the floor, and moved up and down about a million times, while we hashed things over, and over. We even went and looked at the Shays to see how high the stacks were relative to the locomotive cab roofs. And the cardboard stack kept going up and down. To make a long story short, comparing Climax stacks to Shay stacks does not work! Why? Because the exhaust arrangements of Shay and Climax smokeboxes are entirely completely different! Shay exhaust nozzles are very low in the smokebox, with a series of tapered petticoat pipes that direct the exhaust plume as it expands prior to entering the very stubby smokestack tube. On the other hand, the twin exhaust nozzles of Climax locomotives are mounted very high in the smokebox, requiring very tall stacks to ensure that the expanding plume fills the entire inner tube to create the draft for the fire to intensely burn. If one examines photos in the Climax Locomotive book, all Climax stacks are very tall, be they straight, diamond, or Radley-Hunter. I would venture to say that the only way to get a short stacked Climax to steam would be to place a nuclear reactor in the firebox. With this in mind, we are going to make our stack intentionally too tall, bearing in mind that it can be shortened much more readily than extended.

Photo by Rick Brigger