Last night, trains on the JR Yamanote Line and other lines got delayed for about two hours. According to early reports, an object hit the front of the train near Mejiro Station.
I did some overtime work last night so when I arrived at the station the trains were already at halt. I was lucky enough to avoid riding the Yamanote line and getting trapped inside its trains for about two hours. More than 2,000 commuters though were not as lucky as me.
Whenever there is a long delay like in the incident last night, train lines would usually give refunds. In case you have a teiki-ken or regular (pre-paid) train pass, they will issue furikae-jousya-hyou or transfer tickets that you can use in other train lines. Many foreigners do not know about Furikae tickets so they needlessly buy tickets when riding alternative train lines. In my case, I asked for a free transfer ticket and rode the subway from Tokyo station to Ikebukuro station.
Here is a sample image of a furikae ticket.