Both are valid as short stories, although the latter would also fit under the flash fiction label.
Train Trouble is long enough to include two main characters, a minor character and some walk-on parts. It also contains several descriptions of places, indoors and out, and a number of scenes.
A Sticky Interview has two characters and two scenes. Descriptions are sparse and concern themselves with nothing more than the particular topic of the story. Yet, its very length led me to experiment. Where else would I write a sentence like:
The blushes lap at his throat, burning his words.
I haven’t written anything quite like that in a longer short story, and certainly not in a novel. Perhaps I should try it, but would I be able to maintain the style in a longer piece?
I won’t know if I don’t try…