Between the end of the 1990s and the early 2000s, CPTM began the conversion of some metropolitan lines to provide a service similar to rapid transit and better integrate with the São Paulo Metro. Most of the stations where either rebuilt or modernized and new trains were purchased allowing the headway of lines to be as low as four minutes in some lines. This experience started in Line E in the year 2000, in the stretch known as "East Express", serving the east end of São Paulo City and running parallel to Line 3 - Red.