The rail network is getting back to its feet.  With the temperature 
around rising, electric heaters are being turned off.  Blackouts have 
been avoided for the past few days.

The JR East Hachiko Line reopened north of Yorii.  Today the Kururi Line 
in southern Chiba will run all day.  Frequency is still low on the Joban 
Line and the branch out of Abiko.  (This branch is called the "Narita 
Line" for historic reasons but is never used by airport-access trains.)

In addition to Odakyu, Tokyu, Seibu and Tobu, Keikyu and Keio have 
announced revised schedules for April.  Service will be near normal on 
these lines except that some runs will be canceled during the daytime 
and on weekends.

Railways around Sendai are slowly recovering.  Part of the Tohoku Line 
started running yesterday.

JR West says that they may have to cancel local trains which use older 
(JNR era) cars for lack of spare parts.

Details here:
http://www46.atwiki.jp/earthquakeinfo_en/pages/40.html (Tokyo area)
http://www46.atwiki.jp/earthquakeinfo_en/pages/15.html (Tohoku area)