Okawa branch line is local line and single tracked, from Musashi-shiraishi to Okawa (1.0km), the time required is 2 minutes.
Train comes every 8 minutes during rush-hour, in other time every15 minutes or every 40 minutes. Those are operated by Series12 (Kumoha12, manufactured in 1933 as Moha34).
Currently, Okawa branch was merged in Tsurumu line and operates by series 205.