Re: Types of stacks and why chosen

Note also that the Rushton stack is basically the same as the Radley & Hunter. The internal baffles in each work via the same circulation principle. The Rushton simply uses a more streamlined structure and supposedly improves draft somewhat vs the older design.

Dozens of stack designs appeared during the 19th century as local railroads came up with their own designs so as to circumvent patents and royalties. The Southern Pacific stevens stack worked tolerably well for both wood and coal fuel and became a very common sight on west coast railroads.

Diamond stacks often took on various shapes (such as the flattened "pancake" stack) to meet local requirements, like height limits.