Japanese trains were lovely. Very comfortable. Great views of Mt. Fuji and the coast along that route. Definitely options for snack and drink. Don’t know about a full dining car, but it wouldn’t surprise me.
Japanese train food culture is all about buying stuff at the station. The packaged food you can buy at stores in Japan is shockingly good, and they're generally clustered at train stations.
(A cultural note: eating on long-distance trains is expected (they have fold-down tables and cup-holders), but eating or drinking (other than water) on local trains is an EXTREME faux pas. Don't do it.)
(A cultural note: eating on long-distance trains is expected (they have fold-down tables and cup-holders), but eating or drinking (other than water) on local trains is an EXTREME faux pas. Don't do it.)