El is short for "elevated" (i.e. above street level) which many of the CTA (Chcago Transit Authority) trains in the Chicago loop area are (unlike New York which moved most of their elevated railways underground to create their subway system). I do know that the one to O'Hare has segments that are both below ground and at ground level (in the median of a freeway) and may also have elevated segments (I don't remember for sure), but is below ground level in the Chicago downtown "Loop" area.

[This message has been edited by rtpflyer (edited 04-16-2003).]