Indeed, details, figures, animals, baggage, vehicles all change a train set into a "railroad".
I bought many of the original Audrey Thomas books for my son long ago, in london, small format, pre tv shows, great railroad details, as the Rev knew a great deal.
When my son was young, playmobil was
OUR favorite, as it makes for great story telling and hands on play. An unfolding story with its own stage and actors.
I have many such details, (not playmobil) for my trains. Being able to set scenes , for me, is as much fun as running trains.
I so liked the dog, i found one with pup, bowl and bone very cheaply on ebay. Dog shall be a companion to my station master. May get a very healthy black chalk dusting to the muzzle and ears to be a bit more Mastiff-like.
Imagination and Pretend is what its all about