Does anyone have any information about Union Pacific's Chicago Terminal Low Line?

[British Rail Class 142]

Hi, I'd like information about the line mentioned in the title, such as if it's currently used or not, and how frequently it's used. I've been searching the internet for months and have found no information about it at all. If anyone has any information about it, please respond to this post.

If you're wondering, the Chicago Terminal Low Line (formerly owned by C&NW) branches off of the Harvard Subdivision a bit after Metra's Clybourn station.