This is a brief summary of Keio Sagamihara Line train services, based on information available in December 2012, from the point of view of Minami-Ohsawa residents.
Shinjuku is the main destination for Keio trains in central Tokyo. There are two stations at Shinjuku: trains for "Shinjuku" go to the Keio Line station (where they terminate) and trains for "Motoyawata" go to the Keio New Line (where they continue onto the Shinjuku Line of the subway system).
You can reach Shibuya (on the Keio Inokashira Line) for the same price by changing at Mei-Dai-Mae. Journey times to Shibuya are 5-10 minutes longer than to Shinjuku.
A cheap and convenient way to reach Narita Airport is by taking a train which goes via Shinjuku New Line station to Motoyawata. The kyuukou from Minami-Ohsawa goes directly to Motoyawata from late morning until mid-afternoon and takes about 70 minutes; from mid-afternoon the kaisoku goes directly to Motoyawata and takes about 90 minutes. From Motoyawata the Keisei Line goes to Narita Airport and takes about 40 minutes.
MINAMI-OHSAWA - SHINJUKU
For the fastest journey (after about 1100, 35-40 minutes), take the kyuukou or kaisoku and change at Chofu. The connecting train (tokkyuu or jun-tokkyuu, alternately) leaves from the opposite side of the same platform.
If you prefer to stay on the same train all the way, take the kyuukou or kaisoku all the way to Shinjuku. This will add a few minutes to your journey.
Local trains are generally overtaken at Tama Center or Chofu.
During the morning rush hour all trains have slower schedules, and the journey will take 45-60 minutes. In addition, all trains are very crowded, so only travel if you have to. During this period many trains have a "women only" car as the front car of the train.
SHINJUKU - MINAMI-OHSAWA
From about 1000 there is regular 10 minute interval fast service to Chofu (tokkyuu or jun-tokkyuu, alternately), where you can change for a train to Minami-Ohsawa (kyuukou or kaisoku, depending on time of day).
Alternatively, take any Hashimoto-bound kaisoku or kyuukou if you prefer a direct train to Minami-Ohsawa. This adds about 7 minutes to the journey time.
On weekdays, the last train to Minami-Ohsawa leaves Shinjuku at 2350.
On Saturdays, Sundays, and holidays the last train to Minami-Ohsawa leaves at 2333. (Times are correct as of January 2013)
[PLEASE CHECK THESE TIMES AS SCHEDULES CHANGE FREQUENTLY.]
-> Fares/Timegable for Major Stastions of Keio Trains.
Non-local trains leaving Shinjuku in the late evening have a "women only" car as the last car of the train. Non-local early morning trains to Shinjuku have a "women only" car as the front car of the train.