Freight train in subway

Exactly that: I saw a freight train, loaded with cars of industrial equipment (?), pass through a subway station.   

 It was not preceded by an announcement, and no notices were posted.

 Completely unexplained. I like it, though.

This post's theme word is pharate (adj.), "(of an adult insect) Waiting to emerge from a cocoon" or "(of an animal, especially an insect) in transition between stages of development." The pharate equipment slithered through the subway tunnels en route to its mysterious final destination.

Slippery sign

The sign itself was not slippery, it merely indicates the quality of slipperiness. (Which concept --- slipperiness --- indeed often arises in discussions between the sign and the signified!)

Wordlessly evocative.

This post's theme word is arenicolous, "living, growing, or burrowing in sand." The arenicolous ants were at first baffled by the glissant gel coating the floor.