 the purple line of the chicago transit authority is a  branch line on the northernmost section of the chicago 'l' rapid transit network. normally, it extends south from the wilmette terminal at linden avenue, passing through evanston to howard street, on chicago's northern city limits. in september 2012, the average weekday boardings on the purple line was 45,036. the purple line operates weekdays 4:30 a.m. to 1:45 a.m., saturdays 5:05 a.m. to 2:15 a.m., and sundays 6:05 a.m. to 1:45 a.m. during weekday rush hours (approximately 5:20 a.m. to 10:15 a.m. and 2:30 p.m. to 7:10 p.m.), the purple line extends another  south from howard street to downtown chicago running express from howard street to belmont avenue, and then making all local stops to the loop. the express service is known as the purple line express, while the linden-howard shuttle service is the purple line shuttle.train schedules. chicago transit authority. retrieved on 2006-09-23. prior to the color-coding of cta rail lines in 1993, the purple line was known as the evanston line, evanston service, or evanston shuttle, while the purple line express was called the evanston express.purple line. chicago "l".org. retrieved on 2006-09-23. the purple line is useful for reaching northwestern university (davis, foster, and noyes stops 
Chicago_Transit_Authority Evanston,_Illinois Railway_lines_in_Chicago,_Illinois