I rode the BNSF last year during Lolla. I caught it in Aurora. Huge group of young people got on in Downers G. It was jammed when we got downtown. No trouble except when we were around Hinsdale someone on the carriage lit a cigarette. I got my dad voice out & the smoke was quickly extinguished.
Yesterday (Lolla Thursday) is traditionally Metra's busiest day of the year. Also of note is that St. Patrick's Day Saturday is somehow still busier than Lolla Saturday.
Made the mistake of taking my cousin and his two very young kids to the St. Paddy's parade about 15 years ago. People peeing and vomiting at 10am on the sidewalk in the loop. No bathrooms for the 5yo. It was an experience I'm sure they never forgot. lol I think the train was pretty chill though.