Refers to the Shinkansen, Japan's high-speed 'bullet train' network that connects cities at high speed.
東京から大阪まで新幹線で行った。
I went from Tokyo to Osaka by Shinkansen.
新幹線は速くて便利だが、料金は高めだ。
The Shinkansen is fast and convenient, but the fare is somewhat expensive.
週末は指定席がすぐに売り切れることがあるので、新幹線のチケットは早めに買ったほうがいい。
On weekends reserved seats can sell out quickly, so it's better to buy Shinkansen tickets early.