I would personally like to see a rolling stock manufacturer make even a prototype for a modern train with compartments. Seen as the Mk1 compartments had sliding doors to begin with, making a modern version with sliding doors on the outside instead of slam doors shouldn't be terribly difficult!
-Peter
There are modern rolling stock designs with compartment seating eg the DB ICE4 which has been introduced in the past few years in Germany has a few side corridor compartments in first and a few in second class that are specifically designated for families with children.
Compartments can still be found on most long distance trains on the continent in modern rolling stock.
I recently travelled on the Berlin-Warsaw express and nearly the entire train was made up of 3-a-side compartments in second class. The only coaches that were open were the restaurant car and the first class coach (2+1).
The train was modern, comfortable air conditioned stock. Each seat had charging points for phones and laptops, and a control panel so that the occupants could control the heating, lighting and even the volume of the tannoy in the compartment.
The food in the restaurant was great value too, as was the coffee off the trolly.
We do not have to look far to see that we could do so much better for long distance train travel in this country. Doubly so given most of our rolling stock is built or designed abroad.
It is frustrating to be told that such levels of service and comfort are unrealistic to expect in this country when they are so readily encountered at low prices on the continent and once existed here.
It’s not nostalgia- all this stuff is alive and well (and cheap) across the channel!