 the orange line, is a rapid transit line in chicago, illinois run by the chicago transit authority as part of the 'l' system. it is approximately  long and runs at grade and elevated on existing railroad embankments and new concrete and steel structures from chicago midway international airport, the southwest side and downtown chicago. in september 2012, the average weekday boardings on the orange line was 63,037. == route ==  from 
Airport_rail_links_in_the_United_States Chicago_Transit_Authority Railway_lines_in_Chicago,_Illinois