I've been meaning to take a photo of this escalator for awhile. It is the escalator at the North and Clybourn stop on the CTA Red Line. I swear it is the narrowest escalator in the CTA system. It's barely 24 inches wide. With a bulky winter coat and any packages, you have to stand sideways. You also have to stand single file on it so you feel trapped when there are a lot of people riding the escalator. On the other hand, it's a good motivator for taking the stairs.
The North and Clybourn station is the one right by the new Apple Store in Chicago. So, I'm betting it gets a full makeover, complete with a wider escalator, soon.