This project of conversion of lines to metro arose due to the high demand of passengers who use the metropolitan lines of CPTM and the need to recover the old stations.
Between the end of the 1990s and the early 2000s, with this project of refurbishing the CPTM lines, inherited from the RFFSA (Federal Railway Network) and Fepasa (former São Paulo State Railways), the conversion of some metropolitan lines to Metro standard began.