All forms of public transport in Japan offer a very high level of accessibility for travelers with a wide range of impairments.
Here is <information to barrier-free travel in Japan> on the Accessible Japan website.
Plan ahead and always take a contact number with you in case you get lost, are going to be late or have any access problems when you get to your destination.
If you want to take someone with you, this can often help when travelling somewhere for the first time. Sometimes for important meetings it may be worth doing the journey once or twice in advance to make sure everything is OK.