An unusual sight - snow on the train roof

This is something you don't see often in Tokyo: a train with snow on the roof.

Unusually it snowed heavily on Monday, and has been cold since, meaning much of the snow is still lying where it fell. This Chūō-Sōbu Line train E231 series (I think; it could be a 209-500 series) was evidently stabled in the open air when the snow came down and has remained on the roof since. (Apologies for the poor picture quality, by the time I'd noticed and got my camera out the train was already in motion).