Due to The Tohoku earthquake, some railway companies are in trouble.
The factory which produce brushes used in DC motors has to stop working.This is because the factory locates within 30km from Fukushima I Nuclear Power Plant, where nuclear accidents happened. The name of the factory is Hitachi Kasei Industry.
So, trains which need the brushes will have to stop operations in the near future.
According to the article of Toyokeizai online
http://www.toyokeizai.net/business/industrial/detail/AC/96b0fa7a921de0ceaf8d2c88e4694a5d/page/1/
鉄道業界が怯える消耗部品の調達難、ＪＲ西に続く運行本数削減はあるか(Railway companies are afraid of the difficulty preparing comsumable parts. Other companies follow JR west, which firstly decided to reduce train operations.)
The ratio of the trains using the brush produced by Hitachi Kasei
JR West: about 39%
JR East: less than 17%
JR Kyusyu: 0%
Tobu: about 60%
Keikyu: less than 17%
Odakyu: less than 14%
Keisei: 0%
Keio: 0%
Tokyu: 0%
Tokyo metro: about 15%
Kintetsu: about 23%
Hankyu: about 2%
