The amount of "we cannot sell you that ticket, we can't even tell you the price" I have gotten when checking international connections is wild. It is slowly improving (I just checked a particularly absurd example where Deutsche Bahn was unable to sell a ticket to switzerland through if it wasn't bought a long time in advance - seems at least they fixed that), but still... it's absurd if your train trip starts with "figure out how to get a ticket, because the train company won't tell you."