I don't want to go off topic, but I did not want to start the new thread. Shinkansen 100 Series cars which ran on Tokyo - Shin Osaka - Hakata between 1985 and 2004 had two double decker cars.
One of the double decker car was a dining car, upper floor was a dining area and lower floor was a galley (kitchen). Sorry, not inside photo of the dining car. Second double decker car was Green Car, upper floor was standard Green Car with 2x2 seating and lower floor was private room Green Car seats. There was not complimentary drink and food service in this private room Green Car.
Shinkansen 100 Series
Dining Car
Green Car
Green Car Private Room
Maximum speed or Shinkansen 100 Series was 230 km/hr (143 mph) and retirement of 100 Series was one due to make a way to faster Shinkansen train. Currently N700A Series trains run Tokyo - Shin Osaka in maximum speed of 285 km/hr (177 mph). Currently Utsunomiya - Morioka portion of Tohoku Shinkansen is run with maximum speed of 320 km/hr (199 mph). However, Tokyo - Shin Osaka portion of Shinkansen was built in '60s, service of Tokyo - Shin Osaka portion of Shinkansen started in 1964 for Tokyo Olympics. It is now difficult to increase the speed of Tokyo - Shin Osaka portion of Shinkansen by new faster trains. To further increase the speed of Tokyo - Shin Osaka portion of Shinkansen, upgrade of the track is also required and that means service disruption of Shinkansen. Now that JR Tokai is building new Linear Shinkansen (mag lev train) between Shinagawa-Nagoya- Osaka. It is possible that there will be no further speed increase on Tokyo - Shin Osaka portion of Shinkansen.
Also, why no private room Green Car currently on Shinkansen. During the bubble era of Japan, private room Green Car did well on Tokyo - Shin Osaka portion. However, once the bubble era burst, demand of private room Green Car went down. Also, private room Green Car did well at Tokyo - Shin Osaka portion but demand was never there on Shin Osaka - Hakata portion and private room Green Car was often empty on Shin Osaka - Hakata portion.