Last week my friends at Grid Chicago posed this question on their social media channels:

What spelling do you prefer: "L" (The official CTA spelling) or "El" (used by Time Out Chicago and other publications)?

The CTA replied via it Twitter account:

@gridchicago 'L' is correct use, dates back >120 yrs in Chgo; "el" is generic abbrev. for "elevated," 'L' applies to whole system. #settled

I like it. Makes sense. Yes, settled.