Just make a normal working WiFi in trains. Still in 19th century there was a direct train from Saint Petersburg to Nice via Vienna. Nowadays despite a lot of talking about European Union Association for such countries as Ukraine, it is not possible to go by train from Vienna to Kiev directly. The same as during the Cold War, nothing changed.
In the past decade I went by plane between Kiev and Vienna a decent number of times. There are probably a couple of reasons for a lack of a direct train line. One is that Ukrainians need visas to go everywhere in the EU, even next door Poland. Some former members of the Warsaw Pact made it pretty easy for Ukrainians to get visas to visit there, but once Schengen came into force, that all changed. Austria wasn't particularly easy for Ukrainians to get visas for, even before Schengen. The other is that there simply may not be that much demand for it. I've flown into Odessa, Kiev and Donnetsk (RIP Donnetsk Airport, a casualty of fighting in the east), multiple times for the first two and almost always from Vienna on those, and the planes were usually half full at best. On the flight over to Ukraine there were a few times that the plane was mostly full, but on the way to Vienna it almost never was, probably due to the visa issue. Keep in mind too that until roughly 11 years ago Ukraine required visas for just about everybody unless they lived somewhere in the former USSR. Visas were easy to get and Ukraine never had that crazy visa registration nonsense that Russia used to do to tourists, but the fact that you had to get them in advance did discourage a lot of foreigners from going there at the time. On the flights I took, most of the passengers were businessmen. There's been talk of the EU dropping visas for Ukrainians and that has finally gotten approval to negotiate the terms between the EU and Ukraine. Once that happens, the chance of a direct train line may increase. Note that Ukraine, as a former part of the old Russian Empire, uses a different gauge than western Europe, so even if a "direct" line is established, it will require a train change at a border.