One of the main tricks with animation is that the frame names are important. MSTS only animates things with the special names. Some of these are listed in the techdocs supplied on CD1 of MSTS.
I did write some simple tutorials about animating loco wheels and coupling rods, and wiper blades. These used to be on trainsimfiles, but now we have all moved to uktrainsim.com I have not got around to putting them up (they need revising/updating first). If you email me, I can return them.
Important note, the ffeditc.exe program used to compile .S files does not work when animation is included. Either used the uncompiled .S file, or get the ‘fixed’ version of newshape.bnf which is needed to get ffeditc.exe to work properly (again email me and I can send it over).