I've uploaded a tutorial for animating steam loco valve gear in 3ds Max. The tutorial was done in Max 2010, but the included .max files are for Max 8. I've included examples of several different types of valve gear, one having an inclined cylinder/piston. I've also included the Railworks Source folder/files to get the examples into RW. (It may be a day or so before it's in the file library.)
Mike Adams