the commuter line only uses two of those but this is a bit misleading because there are other parallel rail lines over much of its length running right alongsid

the commuter line only uses two of those but this is a bit misleading because there are other parallel rail lines over much of its length running right alongside. there used to be not as many, but the Yamanote was so overcrowded that they constructed additional pairs of tracks to reduce the amount of people who needed to change trains onto the Yamanote.