Yokosuka Line is one of the railways operated by East Japan Railway Company(JR East). It connects Tokyo Station with Kurihama Station in Yokosuka city, Kanagawa prefecture.
The standard trains on the line are 11-car and 15-car. However, a 30-car train ran on Yokosuka Line on December 25th, 2014.
Why did 30-car train run on the line?
The reason is that a 15-car broke down and could not run for itself at Tokyo Station, and that another 15-car train had to pull it to its rail yard.
A 30-car train running is rare, so many rail fans gathered to see it.
Here are videos of 30-car train running.