I drove the route of the P&IN just today (it generally parallels US 95) It's a nice 80-odd mile rail/trail now, and I'm hoping to bike it this fall.
An interesting little back country short line in it's time (later a UP branch). The locals called it the "PIN", not "PAIN". They rostered a McKeen car at one time, which my mother clearly recalls riding in the 1930's. Interestingly, it was called the galloping goose... at a time when the Rio Grande Southern,s geese were just being hatched. I've heard claims that the goose moniker originated with the RGS units, but it just ain't so. Apparently the term was already in the lexicon.
A fellow named Dopf, newspaper publisher in one of the on-line towns wrote a pretty good history of the line.