Originally Posted by
LapLap
Having spent most of last year confined to bed because of back problems, and knowing that the OP is thinking of taking a suitcase from somewhere in Tokyo to the Shinkansen, from there to a hotel in Nagoya and from there to the airport in Nagoya I'm hoping they will be encouraged to just ship it to the airport directly (my guess is that they will have done lots of shopping and it will be pretty full).
Far, far more people have had
real problems with their backs on FT than with Takkyubin (even perceived problems like yours

)
I am sorry to hear about your back. Based on the OP's questions I assumed she/he would be able to carry/pull the suitcase and that her/his only concerns were: 1) how to find escalators/lifts at Tokyo Station, and 2) whether there would be space on Shinkansen to store the case.
BTW, I also assumed that the OP would be spending the night at NGO (the airport) rather than in the city.