Day four of scheduled blackouts and train service reductions.

Also see:
http://donotstuck.blogspot.com/
(More details, but some names are not correctly spelled.)

In case a line closes, as scheduled or not, tickets are not valid for 
parallel lines of other operators.

Following is a summary of official announcements by rail operators.
(compiled 6AM-7AM March 17 2011)

I hope this helps.  Sorry for any shortcomings.


------
Keisei
------

Operations generally along weekend timetable.

Skyliner is running but other extra-fare trains are not.

Reservations for Skyliner will be valid for the run of the given number.
The departure time may change a bit.

(March 17-21)

------
Keikyu
------

Operating on all sections at 80% frequency.
Service to Haneda Airport available.

(March 17-21)


---------------
Haneda Monorail
---------------

Operating along normal timetable.


-------
JR East
-------

Trains are running to Narita Airport, at around 50% frequency.
No Narita Express runs.  (Perhaps this means 1 or 2 local runs per hour.)

Most major lines are running.

No service north of Toride on the Joban Line.
No service north of Kuroiso on the Tohoku Line.
No service on the Ryoumou Line.
Sagami Line closed.

Service disruptions on Ome Line, Itsukaichi Line, Hachiko Line Noon-9PM.
No service on Keiyo Line west of Minami-Funabashi Noon-5PM.
Uchibo Line (Kisarazu and south), Sotobo Line (all sections) closed 8AM-9PM.


For services in the Tohoku area see:
http://traininfo.jreast.co.jp/train_info/e/tohoku.aspx

(The English page for the Tokyo area is out of order.)

----------
JR Central
----------

Tokaido Shinkansen running as usual
  (but getting crowded according to news reports.)

Tokaido Local Line Atami-Fuji will be closed to 5PM.
Minobu Line closed north of Nishi-Fujinomiya all day.
Gotenba Line closed all day.


------------------------
Tokyo Metro, Toei Subway
------------------------

Running with reduced runs.

Part of streetcar Arakawa Line and Toneri Liner will close for some hours.


-----
Tokyu
-----

All sections open.

------
Odakyu
------

Hon-Atsugi - Hadano closed 6AM-10:30AM, 1PM - 6PM.
Hadano - Shin-Matsuda closed 6AM-10:30AM, 1PM-7:30PM
Shin-Matsuda - Odawara closed 2:30PM - 7:30PM

Chogo- Enoshima closed 8:30 - 1:30PM, 4PM-9PM.

Other sections open all day.

(If this schedule continues, you have to start very early from Shinjuku 
to get to stations near Odawara.)


----
Keio
----

All sections open.  Reduced service between 10AM - 4PM featuring
no express service on Inokashira Line, no Special Express on Keio Main 
Line and some extra stops for Semi Special Express and Express.


-----
Seibu
-----

Ikebukuro Line:
closed west of Kotesashi 8:30 - 1:30PM, 2:30PM - 9PM.
closed north of Hannou 1:30PM -2:30PM
No through service to subway.

Whole line open other hours.

Shinjuku Line:

closed north of Shin-Tokorozawa 8:30-1:30PM
closed west of Tanashi 2:30-4:15
closed west of Kami-Shakujii 4:15 - 7:30
closed north of Shin-Tokorozawa 7:30PM - 9PM.

Whole line open other hours.

Seibu-en Line, Haijima Line, Tamako Line closed 2:30 -7:30.
Tamagawa Line closed 11:30 - 4:30.


-----
Tobu
----

Asakusa - Kuki, Minami Kurihashi open all day.
Kuki-Tatebayashi closed 10:15 - 10:50PM.
Tatebayashi - Ota closed from 1:50 onward, but final trains will run.
Ota - Isezaki closed from 8:10 onward, final trains will run.

Sano Line closed 4:55PM onward.
Koizumi Line closed 7:30AM onward, final trains will run.
Kiryu Line closed 7:40AM onward, final trains will run.
(Note that JR Ryoumou Line is also closed.)

Utsunomiya Line starts service 6PM.

Ikebukuro - Shiki open all day.
Shiki - Ogawamachi closed 6PM -10PM.
Ogawamachi - Yorii closed all day.

Omiya - Kasukabe open all day, frequency low on other sections and 
subject to closure.