How can I actually have a usable wifi connection? Cross country train

I have a 10 and a half hour train journey and i want to bring my laptop for some work, thing is, my phone (iD mobile) never seems to be able to pull signal when I’m in the cross country trains + their wifi never works (i’ve done this trip a few times now)

Now i’m desperate though, I need a wifi connection to work, what can I do?