on Sun Jun 28 23:01:07 2020, in response to Re: CHICAGO'S 'L' SYSTEM HAS MYTHS, posted by randyo on Sun Jun 28 15:34:28 2020.
For your interest....original 5000s, 6000s 51-54, 61-65 all could train together. 2000s, 2200s, 2400s, 2600s and 3200s all could train together. Newer 5000s can only train with 5000s series. Expected 7000s likewise......7000s can only train with other 7000s.