Translation:I bought a bullet train ticket.
For those really curious the original Shinkansen was called "chotokkyuu" 超特急 for "Super Limited Express". This was to distinguish it from the then fastest trains (and still operating on some lines) "tokkyuu" 特急 Limited (Special/Exclusive) Express. This name "Super Express" is still used in English announcements. "Bullet Train" is only a nickname that became popular from documentaries and has never officially been used in Japan.