Photos of #168 show that the cylinder block is level. After the very early days of steam locomotives, canted cylinders were quite rare, usually limited to the low pressure cylinders of mallet locomotives to gain ground clearance. Canted cylinders are way more difficult and expensive to make and set up, so were to be avoided.
Also, canted cylinders cause to engine to "walk" more severely under heavy load, by adding more downward thrust to the main driver on the back stroke (and unloading the other than main drivers at the same time).
I would speculate that the drawing you included was drawn in error, unless the T-12's were built that way. In that case, Rio Grande replaced them (and possibly the frames as well?) whenever heavy work was done.
Edited 1 time(s). Last edit at 09/22/2021 08:09AM by Kelly Anderson.