2-8-8-4 wheels. The locomotive's superstructure was attached to the rear group, while the forward group and leading truck could swing laterally on curves. All Yellowstones had fairly small drivers of . (For greater speeds, the Union Pacific Railroad chose a four-wheel leading truck and drivers of for its Big Boy 4-8-8-4 class.) Several classes of Yellowstone, especially the Duluth, Missabe and Iron Range's locomotives, are among the largest steam locomotives, with the exact ranking depending on the criteria used. The Northern Pacific Railway was the first railroad to order a 2-8-8-4. The first was built in 1928 by American Locomotive Company;
Minim (unit) size of a drop can vary considerably depending upon the viscosity and specific gravity of the liquid. (At the time, the phenomenon of surface tension was not well understood.) The minim, on the other hand, was measured with a graduated glass tube known as a "minimometer", later known as the minim-tube. The minim-tube was a type of graduated pipette, a device invented in 1791 by François-Antoine-Henri Descroizilles. Apothecaries' measures are fully defined in the United Kingdom's Weights and Measures Act of 1878, but the UK's 1963 Weights and Measures Act provided for the abolition of the minim, fluid scruple, and