What are the differences between a "Light" Mikado, a "Heavy" Mikado, and is there a "Mikado" in the middle?
I could be wrong, but when people refer to 'Light" and "Heavy" Mikados they are referring to USRA designs. In this case there were only light and heavy. See this link for a brief explanation of the differences. http://www.steamlocomotive.com/mikado/usra.shtml But outside these two standardized versions, were many different Mikados (anything with a 2-8-2 wheel arrangement) made by the various builders for different railroads. Just nothing called a "Medium" Mikado. Regards Ed .
Basically, a Mikado is any engine with a 2 wheel pilot truck, eight driving wheels, and a two wheel trailing truck. Beyond that, differences can be uncountable. Driver sizes varied according to use. Boilers, fireboxes, cylinders. You name it. Boxcab E50
Well as far as I know a Heavy Mikado's a Mikado (meaning 2-8-2) with a higher axle load and boiler. Mikado for heavier loads, simply put.
The Yreka Western has a Mike that was produced for a logging company in Arkansas back in 1915. She has 40 inch drivers and weighs less than 100 tons. This locomotive would be deemed a "light" Mikido because of her limited weight and subsequent tractive effort when conmpared to a "heavy" Mikido.
There were 2-8-2s a lot smaller than the USRA light, many of these for shortlines and logging roads. There were also designs larger than the USRA heavy, and I think NP had the biggest.
