I have to confess to not particularly liking tea or coffee. But I am struck by the fact that in Japan, there is a huge market (and lots of variety) for canned and bottled teas and coffees, which are served hot or cold from vending machines. Are these so much worse than freshly ground coffee that it makes the fuss, cost, danger and risks to profitability worth it?
I know that, overall, trolley service on long distance trains in Japan is regarded very highly, with people being able to buy full (cold) meals in bento boxes, and a wide range of snacks, drinks (including alcoholic drinks), at pretty reasonable prices. For those people who want more variety than that most stations that are not tiny have multiple shops (including sometimes on the platform) also selling catering options to take on to the train - often run by local businesses. On long journeys, it's really not unusual to see most people eating or drinking something they had bought from either the trolley or the station.
Could it be that our British expectation of what is 'proper food' and drink is particularly hard to deliver in a railway setting at prices people are willing to pay? And (somewhat ironically) the Japanese food that is much easier to deliver in a railway environment would, if sold on a British high street, be regarded as 'premium'? I'd love to see someone doing an experiment with Japanese style catering on a train (and I mean real Japanese, not Wagamama or Itsu) to see whether it was popular and profitable.