Dr Risa Nara.
I am a deaf-blind researcher.

I am currently working as an international visiting researcher at the University of Birmingham, UK.

When you ride National Rail in the UK, you can apply for assistance services by various means.

If a blind person wants to use the Japanese bullet train alone, support can be provided in the following ways

Follow the Braille blocks to the manned turnstiles.
Show the station staff your Shinkansen ticket and tell them that you are blind and need help moving around.

Once the station staff have checked your ticket, they will escort you to your seat on the Shinkansen.

The Shinkansen in Japan does not allow you to book assistance services in advance using an app or email.
You must therefore be at the station 30 minutes before the bullet train departs.

I am blind and deaf, but with Japanese trains I can go anywhere by myself.

The train service in Japan is very good.
You should try it yourself.