I'd like to know the difference between an inside frame and an outside frame locomotive. I've seen pictures and actual locomotives that are called by one category or the other, but I can't tell the difference. Thanks in advance, Jim Robinson
Jim, most American steam engines were made with an INSIDE frame, meaning the frame was between the drivers, with the wheels and drive rods on the outside. Look at the engine from the side, if you can see ALL of the big driver wheel, and the frame is behind it, that engine is an INSIDE FRAME engine. Some narrow gauge, and European steam engines were made with the wheels inside between the right and left engine frames, with only the counter weights and drive rods on the outside. This arrangement is known as an OUTSIDE frame engine. Look at this engine from the side, and if you can only see the top and bottom of the drive wheels because the frame hides them, then you are looking at an OUTSIDE FRAME engine. See?
Jim, welcome to Trainboard! I see our answer man, Watash, has already defined inside vs. outside. I'm pretty sure most of the K-28 and K-36 2-8-2's on the Durango and Silverton and Cumbres and Toltec are outside frame. Most other mainline steamers preserved in the USA are inside frame.
