Transport in northern Japan is slowly staggering back to its feet, so I figured it'd be good to have a separate thread for tracking the situation.

Airports

As far as I can tell, all airports except Sendai are operating normally. This includes Fukushima, Iwate-Hanamaki, Yamagata, Odate-Noshiro and Mizawa. Sendai is currently used for relief flights only, no reopening date set yet.

Trains

All major train lines in Tokyo operating, but many running reduced schedules and some special services, notably Narita Express, not operating.

In Tohoku, west coast services are operating normally and local services in the north up to Yonezawa and Ichinoseki will be restored by 3/20. Akita Shinkansen between Akita and Morioka already open, Tohoku Shinkansen from Aomori to Morioka to be restored by 3/23. Map of exact opening schedule, which (based on the URL) will be updated continually:
http://www.jreast.co.jp/pdf/saikaijoukyou.pdf

Still a huge gap in the network between Nasu-Shiobara and Ichinoseki, with eg. every line connected to Sendai entirely out of service. JR East has published a "U-turn route map" showing ways to access many towns with a loop via the west coast, with some gaps covered by bus:
http://www.jreast.co.jp/pdf/ukairoute.pdf

Road

Expressway info from E-NEXCO: http://www.e-nexco.co.jp/
Map view, closed roads in black: http://www.drivetraffic.jp/map.html
Status as of March 18: http://www.e-nexco.co.jp/pressroom/p...ice/h23/0318b/
Map as of March 18: http://www.e-nexco.co.jp/pressroom/p...b/pdfs/112.pdf

Note that many of the sections marked "closed" are, in fact, open to emergency and supply vehicles, and all major towns in Tohoku (incl. Sendai) are accessible by public bus.

There's a useful set of links on transportation status on the JNTO home page: http://www.jnto.go.jp/eng/

Summaries of up-to-date information may be found at:

http://travel.jorudan.co.jp/exit/eq.html (in Japanese - regularly updated)
http://www.jorudan.co.jp/info/english/eq_en.html (in English - not as up-to-date as the Japanese version)
http://eki.jorudan.co.jp/unk/cgi/unk.cgi?pg=1 (live updates by users - in Japanese)

As pointed out in another thread, these folks have been doing a great job of publishing English language transit updates:

http://donotstuck.blogspot.com/

Yes, but as the website acknowledges the source is the Japanese version of jorudan and it cannot be as up-to-date as the original for obvious reasons.

If anyone wants the latest infomation I suggest using Google Translate.
http://translate.google.com/translat...exit%2Feq.html

Including Ferries:

http://www.jnto.go.jp/eq/ferry_eng.pdf

The Ministry of Land, Infrastructure, Transport and Tourism also has an overview map of the current status available on their website. Direct URL:
http://www.mlit.go.jp/common/000138153.pdf (this one from 16:00 19th March 2011).

Slightly OT but I was looking at arrival and departure info at NRT and the following airlines appear to be operating European flights to/from NRT with a "technical stop".

AF - ICN (direct flight resumed on 8 April)
AY - NGO (direct flight resumed on 26 March)
AZ - KIX (resuming flights 24 March w/ refueling stop on flights from Italy)
BA - HKG (LHR-HND flights cancelled due to a reduced demand)
KL - KIX
LH - ICN (resuming direct flights on 15 April)
LX - NGO (resuming direct flights on 15 April)
OS - PEK (resuming direct flights on 16 April)
TK (resuming non-stop flights to/from IST)

The following airlines appear to be flying directly to NRT: JL NH VS SK.

JR Sendai has published a list of the train lines that are expected to be back in operation by the first week of April or so -- they're making rapid progress and some lines around Sendai will start operating shortly, but Sendai will still remain cut off from the bulk of the network. Also, while the Yamagata Shinkansen will start operating between Yamagata and Fukushima soon, there's still not even an estimated date for resumption of the Tohoku Shinkansen.

http://www.jr-tabi.com/eq.html

More positively, and in fact rather incredibly, all major roads in the Tohoku region, including the worst-hit Sanriku coast are, are now usable and open to the public again (excluding the nuclear plant exclusion zone, that is). Only some expressway sections around Sendai remain reserved for emergency vehicles.

http://www.mlit.go.jp/common/000138153.pdf

Also, while the N'Ex is still suspended, I am reading that service has been restored on the rapid Airport Narita service that, as I recall, runs about twice an hour. Keisei Skyliner remains available as an excellent alternative.

Thank you all for keeping us posted and updated.

Question: is the Nagano Shinkansen on normal service?

The Nagano Shinkansen is running as normal with the exception of Asama 577 (Tokyo 16:04 - Nagano 17:46).

Tokaido Shinkansen : Normal service expected.
Tohoku Shinkansen : Tokyo-Nasushiobara (2 trains per hour), Morioka-Aomori (10 trains per day), no service between Nasushiobara-Morioka
Yamagata Shinkansen : No service
Akita Shinkansen : Reduced service Morioka-Akita (5 trains per day)
Joetsu Shinkansen : Service running except Max Tanigawa 71,75,79,80, Tanigawa 82,84)
Nagano Shinkansen : Normal service except Asama 577

Air conditioners on some trains are being turned off to reduce elecrtricity consumption. Unpack your jacket or sweater after arriving in Tokyo.

Keisei Skyliner/Sky Access : running weekend schedule

Limousine Bus : all services operating with the following exceptions
- Not stopping at the Shangri La Tokyo which is closed temporarily following the earthquake
- Tokyo Disney Resort & Shin-urayasu areas
- Kichijoji station (service will resume on 29 March)

Narita Express : no service

Airport Express (JR to Tokyo, Shinagawa, Yokohama) : normal service

http://e.nikkei.com/e/fr/tnks/Nni20110328D28JF246.htm

So that will bring an end to natto shortages.