Here some fun facts about the about the bullet train in Japan.
You’ll struggle to find bullet train references in Japan. Use the correct word - shinkansen - which means new main line. When in Japan, look out for shinkansen signage.
On the Joetsu shinkansen line, the 14.8 km Nakayama Tunnel 中山トンネル deviations slow down the train to just 160 km/h. Construction was difficult, with water flooding and a new route inside the mountain was needed. Kanji readers will translate with ease: Nakayama means middle mountain.
On the subject of tunnels, more than half the 553.7 on Sanyo shinkansen is in tunnel - with several over 15 km long. When travelling on this route, make the most of the glimpses of passing Japanese countryside.
As well as full sized shinkansen, there is also the mini-shinkansen. These trains operate both on the dedicated high speed line and on two secondary routes converted converted for shinkansen use. These trains have narrow profile and special retractable steps which are deployed on converted routes.
An eastbound shinkansen train emerges from the 7.9 km Kobe tunnel, to stop at Shin-Kobe station. When the train leaves this station, it will immediately enter the 16.2 km Rokko tunnel. Picture taken by Nicholas Stone, the author of this answer.