What Is This? *solved!

Have seen a few of these in the game. What exactly is it?
It's not something I've ever seen on a North American railway track before and we do have a few different things along the tracks.

 

Looks like some kind of flange lubricator.

 

Hmmmm? It's yellow/black and some what dirty..But what it's for remains a mystery.

 

Probably a flange lubricator, as Dangerous Dave said - used to reduce wear on wheels and rails.

 

Yes, I looked up "Flange Lubricator" as your suggestions and it is definitely that. Thanks for the pointer guys!
Primarily of UK design...