M4 is one of the five lines of the Bucharest Metro. It is currently 7.44 km long and runs from Gara Progresul to Străulești, following the Griviței and Bucureștii Noi avenues. M4 is the only line that has Astra IVAs which are the oldest trains from the bucharest metro. It is a female line because of its speaker announcements. This line corresponds with 2 lines, M6 at the 1 mai station and M0 at its terminal, straulesti. At the bottom, M5 corresponds with M4 At Cismigiu.